notebooks/Spawning-Classes.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Spawning classes\n",
    "\n",
    "This and other notebooks for this video series are found at \n",
    "\n",
    "https://github.com/vathes/db-programming-with-datajoint\n",
    "\n",
    "This notebook describes how to work with database schemas without access to the original code that generated the schema. These situations often arise when the database is created by another user who has not shared the generating code yet or when the database schema is created from a programming language other than Python. "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "scrolled": true
   },
   "outputs": [],
   "source": [
    "import datajoint as dj"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Working with schemas and their modules\n",
    "\n",
    "Typically a DataJoint schema is created as a dedicated Python module. This module defines a `schema` object that is used to link classes declared in the module to tables in the database schema. As an example, examine the `university` module in this folder (`./university.py`).\n",
    "\n",
    "You may then import the module to interact with its tables:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Connecting dimitri@localhost:3306\n"
     ]
    }
   ],
   "source": [
    "import university as uni"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "data": {
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       "<svg height=\"327pt\" viewBox=\"0.00 0.00 413.50 327.00\" width=\"414pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">\n",
       "<g class=\"graph\" id=\"graph0\" transform=\"scale(1 1) rotate(0) translate(4 323)\">\n",
       "<title>%3</title>\n",
       "<polygon fill=\"#ffffff\" points=\"-4,4 -4,-323 409.5,-323 409.5,4 -4,4\" stroke=\"transparent\"/>\n",
       "<!-- uni.LetterGrade -->\n",
       "<g class=\"node\" id=\"node1\">\n",
       "<title>uni.LetterGrade</title>\n",
       "<g id=\"a_node1\"><a xlink:title=\"grade                \r",
       "------------------------------\r",
       "points               \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"99,-106 0,-106 0,-71 99,-71 99,-106\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"8\" y=\"-86.4\">uni.LetterGrade</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Grade -->\n",
       "<g class=\"node\" id=\"node4\">\n",
       "<title>uni.Grade</title>\n",
       "<g id=\"a_node4\"><a xlink:title=\"→ uni.Enroll\r",
       "------------------------------\r",
       "→ uni.LetterGrade\r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"135,-35 66,-35 66,0 135,0 135,-35\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"middle\" x=\"100.5\" y=\"-14.4\">uni.Grade</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.LetterGrade&#45;&gt;uni.Grade -->\n",
       "<g class=\"edge\" id=\"edge1\">\n",
       "<title>uni.LetterGrade-&gt;uni.Grade</title>\n",
       "<path d=\"M62.1067,-70.9494C69.894,-60.1083 79.8582,-46.2366 87.684,-35.3418\" fill=\"none\" stroke=\"#000000\" stroke-dasharray=\"5,2\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.CurrentTerm -->\n",
       "<g class=\"node\" id=\"node2\">\n",
       "<title>uni.CurrentTerm</title>\n",
       "<g id=\"a_node2\"><a xlink:title=\"omega                \r",
       "------------------------------\r",
       "→ uni.Term\r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"405.5,-177 303.5,-177 303.5,-142 405.5,-142 405.5,-177\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"311.5\" y=\"-157.4\">uni.CurrentTerm</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Course -->\n",
       "<g class=\"node\" id=\"node3\">\n",
       "<title>uni.Course</title>\n",
       "<g id=\"a_node3\"><a xlink:title=\"→ uni.Department\r",
       "course               \r",
       "------------------------------\r",
       "course_name          \r",
       "credits              \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"290,-248 215,-248 215,-213 290,-213 290,-248\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"223\" y=\"-228.4\">uni.Course</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Section -->\n",
       "<g class=\"node\" id=\"node6\">\n",
       "<title>uni.Section</title>\n",
       "<g id=\"a_node6\"><a xlink:title=\"→ uni.Course\r",
       "→ uni.Term\r",
       "section              \r",
       "------------------------------\r",
       "auditorium           \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"285,-177 208,-177 208,-142 285,-142 285,-177\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"216\" y=\"-157.4\">uni.Section</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Course&#45;&gt;uni.Section -->\n",
       "<g class=\"edge\" id=\"edge2\">\n",
       "<title>uni.Course-&gt;uni.Section</title>\n",
       "<path d=\"M251.0169,-212.9494C250.1007,-202.1083 248.9284,-188.2366 248.0078,-177.3418\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.Term -->\n",
       "<g class=\"node\" id=\"node5\">\n",
       "<title>uni.Term</title>\n",
       "<g id=\"a_node5\"><a xlink:title=\"term_year            \r",
       "term                 \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"380.5,-248 318.5,-248 318.5,-213 380.5,-213 380.5,-248\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"326.5\" y=\"-228.4\">uni.Term</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Term&#45;&gt;uni.CurrentTerm -->\n",
       "<g class=\"edge\" id=\"edge3\">\n",
       "<title>uni.Term-&gt;uni.CurrentTerm</title>\n",
       "<path d=\"M350.736,-212.9494C351.4994,-202.1083 352.4763,-188.2366 353.2435,-177.3418\" fill=\"none\" stroke=\"#000000\" stroke-dasharray=\"5,2\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.Term&#45;&gt;uni.Section -->\n",
       "<g class=\"edge\" id=\"edge4\">\n",
       "<title>uni.Term-&gt;uni.Section</title>\n",
       "<path d=\"M324.0393,-212.9494C308.193,-202.0262 287.8831,-188.0262 272.0248,-177.0947\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.Enroll -->\n",
       "<g class=\"node\" id=\"node10\">\n",
       "<title>uni.Enroll</title>\n",
       "<g id=\"a_node10\"><a xlink:title=\"→ uni.Student\r",
       "→ uni.Section\r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"185.5,-106 117.5,-106 117.5,-71 185.5,-71 185.5,-106\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"middle\" x=\"151.5\" y=\"-85.4\">uni.Enroll</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Section&#45;&gt;uni.Enroll -->\n",
       "<g class=\"edge\" id=\"edge5\">\n",
       "<title>uni.Section-&gt;uni.Enroll</title>\n",
       "<path d=\"M223.0168,-141.9494C208.4013,-131.0262 189.6689,-117.0262 175.0422,-106.0947\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.Department -->\n",
       "<g class=\"node\" id=\"node7\">\n",
       "<title>uni.Department</title>\n",
       "<g id=\"a_node7\"><a xlink:title=\"dept                 \r",
       "------------------------------\r",
       "dept_name            \r",
       "dept_address         \r",
       "dept_phone           \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"279.5,-319 181.5,-319 181.5,-284 279.5,-284 279.5,-319\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"189.5\" y=\"-299.4\">uni.Department</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Department&#45;&gt;uni.Course -->\n",
       "<g class=\"edge\" id=\"edge6\">\n",
       "<title>uni.Department-&gt;uni.Course</title>\n",
       "<path d=\"M235.9382,-283.9494C239.2974,-273.1083 243.5957,-259.2366 246.9715,-248.3418\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.StudentMajor -->\n",
       "<g class=\"node\" id=\"node8\">\n",
       "<title>uni.StudentMajor</title>\n",
       "<g id=\"a_node8\"><a xlink:title=\"→ uni.Student\r",
       "------------------------------\r",
       "→ uni.Department\r",
       "declare_date         \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"197,-248 90,-248 90,-213 197,-213 197,-248\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"middle\" x=\"143.5\" y=\"-227.4\">uni.StudentMajor</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Department&#45;&gt;uni.StudentMajor -->\n",
       "<g class=\"edge\" id=\"edge7\">\n",
       "<title>uni.Department-&gt;uni.StudentMajor</title>\n",
       "<path d=\"M208.9944,-283.9494C195.6096,-273.0262 178.4547,-259.0262 165.0597,-248.0947\" fill=\"none\" stroke=\"#000000\" stroke-dasharray=\"5,2\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.Student -->\n",
       "<g class=\"node\" id=\"node9\">\n",
       "<title>uni.Student</title>\n",
       "<g id=\"a_node9\"><a xlink:title=\"student_id           \r",
       "------------------------------\r",
       "first_name           \r",
       "last_name            \r",
       "sex                  \r",
       "date_of_birth        \r",
       "home_address         \r",
       "home_city            \r",
       "home_state           \r",
       "home_zip             \r",
       "home_phone           \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"141,-319 64,-319 64,-284 141,-284 141,-319\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"72\" y=\"-299.4\">uni.Student</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Student&#45;&gt;uni.StudentMajor -->\n",
       "<g class=\"edge\" id=\"edge8\">\n",
       "<title>uni.Student-&gt;uni.StudentMajor</title>\n",
       "<path d=\"M112.6348,-283.9494C118.8952,-273.1083 126.9056,-259.2366 133.197,-248.3418\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\"2\"/>\n",
       "</g>\n",
       "<!-- uni.Student&#45;&gt;uni.Enroll -->\n",
       "<g class=\"edge\" id=\"edge9\">\n",
       "<title>uni.Student-&gt;uni.Enroll</title>\n",
       "<path d=\"M92.8006,-283.828C84.2254,-265.9346 74.0088,-237.4857 80.5,-213 91.5306,-171.3909 120.077,-129.1624 137.428,-106.1537\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.Enroll&#45;&gt;uni.Grade -->\n",
       "<g class=\"edge\" id=\"edge10\">\n",
       "<title>uni.Enroll-&gt;uni.Grade</title>\n",
       "<path d=\"M138.8933,-70.9494C131.106,-60.1083 121.1418,-46.2366 113.316,-35.3418\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\"2\"/>\n",
       "</g>\n",
       "</g>\n",
       "</svg>"
      ],
      "text/plain": [
       "<datajoint.diagram.Diagram at 0x7f27eba62630>"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "dj.Diagram(uni)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Note that `dj.Diagram` can extract the diagram from a schema object or from a python module containing its `schema` object, lending further support to the convention of one-to-one correspondence between database schemas and Python modules in a datajoint project:\n",
    "```python\n",
    "dj.Diagram(uni)\n",
    "```\n",
    "is equvalent to \n",
    "```python\n",
    "dj.Diagram(uni.schema)\n",
    "```"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "\n",
       "        \n",
       "        <style type=\"text/css\">\n",
       "            .Relation{\n",
       "                border-collapse:collapse;\n",
       "            }\n",
       "            .Relation th{\n",
       "                background: #A0A0A0; color: #ffffff; padding:4px; border:#f0e0e0 1px solid;\n",
       "                font-weight: normal; font-family: monospace; font-size: 100%;\n",
       "            }\n",
       "            .Relation td{\n",
       "                padding:4px; border:#f0e0e0 1px solid; font-size:100%;\n",
       "            }\n",
       "            .Relation tr:nth-child(odd){\n",
       "                background: #ffffff;\n",
       "            }\n",
       "            .Relation tr:nth-child(even){\n",
       "                background: #f3f1ff;\n",
       "            }\n",
       "            /* Tooltip container */\n",
       "            .djtooltip {\n",
       "            }\n",
       "            /* Tooltip text */\n",
       "            .djtooltip .djtooltiptext {\n",
       "                visibility: hidden;\n",
       "                width: 120px;\n",
       "                background-color: black;\n",
       "                color: #fff;\n",
       "                text-align: center;\n",
       "                padding: 5px 0;\n",
       "                border-radius: 6px;\n",
       "                /* Position the tooltip text - see examples below! */\n",
       "                position: absolute;\n",
       "                z-index: 1;\n",
       "            }\n",
       "            #primary {\n",
       "                font-weight: bold;\n",
       "                color: black;\n",
       "            }\n",
       "\n",
       "            #nonprimary {\n",
       "                font-weight: normal;\n",
       "                color: white;\n",
       "            }\n",
       "\n",
       "            /* Show the tooltip text when you mouse over the tooltip container */\n",
       "            .djtooltip:hover .djtooltiptext {\n",
       "                visibility: visible;\n",
       "            }\n",
       "        </style>\n",
       "        \n",
       "        <b></b>\n",
       "            <div style=\"max-height:1000px;max-width:1500px;overflow:auto;\">\n",
       "            <table border=\"1\" class=\"Relation\">\n",
       "                <thead> <tr style=\"text-align: right;\"> <th> <div class=\"djtooltip\">\n",
       "                                <p id=\"primary\">student_id</p>\n",
       "                                <span class=\"djtooltiptext\">university-wide ID number</span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">first_name</p>\n",
       "                                <span class=\"djtooltiptext\"></span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">last_name</p>\n",
       "                                <span class=\"djtooltiptext\"></span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">sex</p>\n",
       "                                <span class=\"djtooltiptext\"></span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">date_of_birth</p>\n",
       "                                <span class=\"djtooltiptext\"></span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">home_address</p>\n",
       "                                <span class=\"djtooltiptext\">mailing street address</span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">home_city</p>\n",
       "                                <span class=\"djtooltiptext\">mailing address</span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">home_state</p>\n",
       "                                <span class=\"djtooltiptext\">US state acronym: e.g. OH</span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">home_zip</p>\n",
       "                                <span class=\"djtooltiptext\">zipcode e.g. 93979-4979</span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">home_phone</p>\n",
       "                                <span class=\"djtooltiptext\">e.g. 414.657.6883x0881</span>\n",
       "                            </div> </th> </tr> </thead>\n",
       "                <tbody> <tr> <td>1003</td>\n",
       "<td>Jonathan</td>\n",
       "<td>Wilson</td>\n",
       "<td>M</td>\n",
       "<td>2002-10-19</td>\n",
       "<td>91101 Summer Park</td>\n",
       "<td>Port Jacqueline</td>\n",
       "<td>VT</td>\n",
       "<td>75616</td>\n",
       "<td>982.251.1567x21450</td></tr><tr><td>1005</td>\n",
       "<td>Richard</td>\n",
       "<td>Lopez</td>\n",
       "<td>M</td>\n",
       "<td>1993-10-16</td>\n",
       "<td>86210 Brooks Station</td>\n",
       "<td>West David</td>\n",
       "<td>IL</td>\n",
       "<td>96184</td>\n",
       "<td>+1-385-481-6761x1575</td></tr><tr><td>1006</td>\n",
       "<td>Laura</td>\n",
       "<td>Hammond</td>\n",
       "<td>F</td>\n",
       "<td>1984-12-03</td>\n",
       "<td>0346 Shannon Motorway</td>\n",
       "<td>East David</td>\n",
       "<td>ME</td>\n",
       "<td>22113</td>\n",
       "<td>(189)406-2652x143</td> </tr> </tbody>\n",
       "            </table>\n",
       "            <p>...</p>\n",
       "            <p>Total: 751</p></div>\n",
       "            "
      ],
      "text/plain": [
       "*student_id    first_name     last_name     sex     date_of_birth  home_address   home_city      home_state     home_zip     home_phone    \n",
       "+------------+ +------------+ +-----------+ +-----+ +------------+ +------------+ +------------+ +------------+ +----------+ +------------+\n",
       "1003           Jonathan       Wilson        M       2002-10-19     91101 Summer P Port Jacquelin VT             75616        982.251.1567x2\n",
       "1005           Richard        Lopez         M       1993-10-16     86210 Brooks S West David     IL             96184        +1-385-481-676\n",
       "1006           Laura          Hammond       F       1984-12-03     0346 Shannon M East David     ME             22113        (189)406-2652x\n",
       "   ...\n",
       " (Total: 751)"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# students without majors \n",
    "uni.Student - uni.StudentMajor"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Spawning missing classes\n",
    "Now imagine that you do not have access to `university.py` or you do not have its latest version. You can still connect to the database schema but you will not have classes declared to interact with it.\n",
    "\n",
    "So let's start over in this scenario.\n",
    "\n",
    "### <font color=\"green\">**!!! Restart the kernel here to remove the previous class definitions !!!**</font>"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "You can may use the `dj.list_schemas` function (new in `datajoint 0.12.0`) to list the names of database schemas available to you."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Connecting dimitri@localhost:3306\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "['dimitri_alter',\n",
       " 'dimitri_attach',\n",
       " 'dimitri_blob',\n",
       " 'dimitri_blobs',\n",
       " 'dimitri_nphoton',\n",
       " 'dimitri_schema',\n",
       " 'dimitri_university',\n",
       " 'dimitri_uuid',\n",
       " 'university']"
      ]
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "import datajoint as dj\n",
    "dj.list_schemas()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Just as with a new schema, we start by creating a `schema` object to connect to the chosen database schema:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "schema = dj.schema('dimitri_university')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "If the schema already exists, `dj.schema` is initialized as usual and you may plot the schema diagram. But instead of seeing class names, you will see the raw table names as they appear in the database."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "data": {
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       "<g class=\"graph\" id=\"graph0\" transform=\"scale(1 1) rotate(0) translate(4 323)\">\n",
       "<title>%3</title>\n",
       "<polygon fill=\"#ffffff\" points=\"-4,4 -4,-323 736.5,-323 736.5,4 -4,4\" stroke=\"transparent\"/>\n",
       "<!-- `dimitri_university`.`course` -->\n",
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       "<title>`dimitri_university`.`course`</title>\n",
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       "</g>\n",
       "<!-- `dimitri_university`.`section` -->\n",
       "<g class=\"node\" id=\"node7\">\n",
       "<title>`dimitri_university`.`section`</title>\n",
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       "</g>\n",
       "<!-- `dimitri_university`.`course`&#45;&gt;`dimitri_university`.`section` -->\n",
       "<g class=\"edge\" id=\"edge1\">\n",
       "<title>`dimitri_university`.`course`-&gt;`dimitri_university`.`section`</title>\n",
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       "</g>\n",
       "<!-- `dimitri_university`.`current_term` -->\n",
       "<g class=\"node\" id=\"node2\">\n",
       "<title>`dimitri_university`.`current_term`</title>\n",
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       "</g>\n",
       "<!-- `dimitri_university`.`department` -->\n",
       "<g class=\"node\" id=\"node3\">\n",
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       "</g>\n",
       "<!-- `dimitri_university`.`department`&#45;&gt;`dimitri_university`.`course` -->\n",
       "<g class=\"edge\" id=\"edge2\">\n",
       "<title>`dimitri_university`.`department`-&gt;`dimitri_university`.`course`</title>\n",
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       "<!-- `dimitri_university`.`department`&#45;&gt;`dimitri_university`.`student_major` -->\n",
       "<g class=\"edge\" id=\"edge3\">\n",
       "<title>`dimitri_university`.`department`-&gt;`dimitri_university`.`student_major`</title>\n",
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       "</g>\n",
       "<!-- `dimitri_university`.`enroll` -->\n",
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       "<!-- `dimitri_university`.`grade` -->\n",
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       "<!-- `dimitri_university`.`enroll`&#45;&gt;`dimitri_university`.`grade` -->\n",
       "<g class=\"edge\" id=\"edge4\">\n",
       "<title>`dimitri_university`.`enroll`-&gt;`dimitri_university`.`grade`</title>\n",
       "<path d=\"M260.5168,-70.9494C245.9013,-60.0262 227.1689,-46.0262 212.5422,-35.0947\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\"2\"/>\n",
       "</g>\n",
       "<!-- `dimitri_university`.`letter_grade` -->\n",
       "<g class=\"node\" id=\"node6\">\n",
       "<title>`dimitri_university`.`letter_grade`</title>\n",
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       "</g>\n",
       "<!-- `dimitri_university`.`letter_grade`&#45;&gt;`dimitri_university`.`grade` -->\n",
       "<g class=\"edge\" id=\"edge5\">\n",
       "<title>`dimitri_university`.`letter_grade`-&gt;`dimitri_university`.`grade`</title>\n",
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       "</g>\n",
       "<!-- `dimitri_university`.`section`&#45;&gt;`dimitri_university`.`enroll` -->\n",
       "<g class=\"edge\" id=\"edge6\">\n",
       "<title>`dimitri_university`.`section`-&gt;`dimitri_university`.`enroll`</title>\n",
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       "</g>\n",
       "<!-- `dimitri_university`.`student` -->\n",
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       "<title>`dimitri_university`.`student`</title>\n",
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       "<!-- `dimitri_university`.`student`&#45;&gt;`dimitri_university`.`enroll` -->\n",
       "<g class=\"edge\" id=\"edge7\">\n",
       "<title>`dimitri_university`.`student`-&gt;`dimitri_university`.`enroll`</title>\n",
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       "</g>\n",
       "<!-- `dimitri_university`.`student`&#45;&gt;`dimitri_university`.`student_major` -->\n",
       "<g class=\"edge\" id=\"edge8\">\n",
       "<title>`dimitri_university`.`student`-&gt;`dimitri_university`.`student_major`</title>\n",
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       "<!-- `dimitri_university`.`term` -->\n",
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       "</g>\n",
       "<!-- `dimitri_university`.`term`&#45;&gt;`dimitri_university`.`current_term` -->\n",
       "<g class=\"edge\" id=\"edge9\">\n",
       "<title>`dimitri_university`.`term`-&gt;`dimitri_university`.`current_term`</title>\n",
       "<path d=\"M633.236,-212.9494C633.9994,-202.1083 634.9763,-188.2366 635.7435,-177.3418\" fill=\"none\" stroke=\"#000000\" stroke-dasharray=\"5,2\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- `dimitri_university`.`term`&#45;&gt;`dimitri_university`.`section` -->\n",
       "<g class=\"edge\" id=\"edge10\">\n",
       "<title>`dimitri_university`.`term`-&gt;`dimitri_university`.`section`</title>\n",
       "<path d=\"M585.0337,-212.9494C555.8026,-202.0262 518.3378,-188.0262 489.0845,-177.0947\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "</g>\n",
       "</svg>"
      ],
      "text/plain": [
       "<datajoint.diagram.Diagram at 0x7f9b73274940>"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# let's plot its diagram\n",
    "dj.Diagram(schema)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "You may view the diagram but, at this point, there is now way to interact with these tables. A similar situation arises when another developer has added new tables to the schema but has not yet shared the updated module code with you. Then the diagram will show a mixture of class names and database table names.\n",
    "\n",
    "Now you may use the `schema.spawn_missing_classes` method to *spawn* classes into the local namespace for any tables missing their classes:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
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       "<g class=\"graph\" id=\"graph0\" transform=\"scale(1 1) rotate(0) translate(4 323)\">\n",
       "<title>%3</title>\n",
       "<polygon fill=\"#ffffff\" points=\"-4,4 -4,-323 333.5,-323 333.5,4 -4,4\" stroke=\"transparent\"/>\n",
       "<!-- Course -->\n",
       "<g class=\"node\" id=\"node1\">\n",
       "<title>Course</title>\n",
       "<g id=\"a_node1\"><a xlink:title=\"→ Department\r",
       "course               \r",
       "------------------------------\r",
       "course_name          \r",
       "credits              \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"233,-248 177,-248 177,-213 233,-213 233,-248\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
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       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- Section -->\n",
       "<g class=\"node\" id=\"node9\">\n",
       "<title>Section</title>\n",
       "<g id=\"a_node9\"><a xlink:title=\"→ Course\r",
       "→ Term\r",
       "section              \r",
       "------------------------------\r",
       "auditorium           \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"228.5,-177 171.5,-177 171.5,-142 228.5,-142 228.5,-177\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"179.5\" y=\"-157.4\">Section</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- Course&#45;&gt;Section -->\n",
       "<g class=\"edge\" id=\"edge1\">\n",
       "<title>Course-&gt;Section</title>\n",
       "<path d=\"M203.764,-212.9494C203.0006,-202.1083 202.0237,-188.2366 201.2565,-177.3418\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- Grade -->\n",
       "<g class=\"node\" id=\"node2\">\n",
       "<title>Grade</title>\n",
       "<g id=\"a_node2\"><a xlink:title=\"→ Enroll\r",
       "------------------------------\r",
       "→ LetterGrade\r",
       "\">\n",
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       "</g>\n",
       "</g>\n",
       "<!-- Department -->\n",
       "<g class=\"node\" id=\"node3\">\n",
       "<title>Department</title>\n",
       "<g id=\"a_node3\"><a xlink:title=\"dept                 \r",
       "------------------------------\r",
       "dept_name            \r",
       "dept_address         \r",
       "dept_phone           \r",
       "\">\n",
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       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"153.5\" y=\"-299.4\">Department</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- Department&#45;&gt;Course -->\n",
       "<g class=\"edge\" id=\"edge2\">\n",
       "<title>Department-&gt;Course</title>\n",
       "<path d=\"M189.9438,-283.9494C192.9976,-273.1083 196.9052,-259.2366 199.9741,-248.3418\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- StudentMajor -->\n",
       "<g class=\"node\" id=\"node5\">\n",
       "<title>StudentMajor</title>\n",
       "<g id=\"a_node5\"><a xlink:title=\"→ Student\r",
       "------------------------------\r",
       "→ Department\r",
       "declare_date         \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"159,-248 71,-248 71,-213 159,-213 159,-248\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"middle\" x=\"115\" y=\"-227.4\">StudentMajor</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- Department&#45;&gt;StudentMajor -->\n",
       "<g class=\"edge\" id=\"edge3\">\n",
       "<title>Department-&gt;StudentMajor</title>\n",
       "<path d=\"M167.6966,-283.9494C157.0082,-273.1083 143.3318,-259.2366 132.5905,-248.3418\" fill=\"none\" stroke=\"#000000\" stroke-dasharray=\"5,2\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- Enroll -->\n",
       "<g class=\"node\" id=\"node4\">\n",
       "<title>Enroll</title>\n",
       "<g id=\"a_node4\"><a xlink:title=\"→ Student\r",
       "→ Section\r",
       "\">\n",
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       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"middle\" x=\"122\" y=\"-85.4\">Enroll</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- Enroll&#45;&gt;Grade -->\n",
       "<g class=\"edge\" id=\"edge4\">\n",
       "<title>Enroll-&gt;Grade</title>\n",
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       "</g>\n",
       "<!-- Student -->\n",
       "<g class=\"node\" id=\"node6\">\n",
       "<title>Student</title>\n",
       "<g id=\"a_node6\"><a xlink:title=\"student_id           \r",
       "------------------------------\r",
       "first_name           \r",
       "last_name            \r",
       "sex                  \r",
       "date_of_birth        \r",
       "home_address         \r",
       "home_city            \r",
       "home_state           \r",
       "home_zip             \r",
       "home_phone           \r",
       "\">\n",
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       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- Student&#45;&gt;Enroll -->\n",
       "<g class=\"edge\" id=\"edge5\">\n",
       "<title>Student-&gt;Enroll</title>\n",
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       "</g>\n",
       "<!-- Student&#45;&gt;StudentMajor -->\n",
       "<g class=\"edge\" id=\"edge6\">\n",
       "<title>Student-&gt;StudentMajor</title>\n",
       "<path d=\"M87.8989,-283.9494C93.3958,-273.1083 100.4293,-259.2366 105.9534,-248.3418\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\"2\"/>\n",
       "</g>\n",
       "<!-- LetterGrade -->\n",
       "<g class=\"node\" id=\"node7\">\n",
       "<title>LetterGrade</title>\n",
       "<g id=\"a_node7\"><a xlink:title=\"grade                \r",
       "------------------------------\r",
       "points               \r",
       "\">\n",
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       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- LetterGrade&#45;&gt;Grade -->\n",
       "<g class=\"edge\" id=\"edge7\">\n",
       "<title>LetterGrade-&gt;Grade</title>\n",
       "<path d=\"M50.1348,-70.9494C56.3952,-60.1083 64.4056,-46.2366 70.697,-35.3418\" fill=\"none\" stroke=\"#000000\" stroke-dasharray=\"5,2\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- Term -->\n",
       "<g class=\"node\" id=\"node8\">\n",
       "<title>Term</title>\n",
       "<g id=\"a_node8\"><a xlink:title=\"term_year            \r",
       "term                 \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"304.5,-248 261.5,-248 261.5,-213 304.5,-213 304.5,-248\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"269.5\" y=\"-228.4\">Term</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- Term&#45;&gt;Section -->\n",
       "<g class=\"edge\" id=\"edge8\">\n",
       "<title>Term-&gt;Section</title>\n",
       "<path d=\"M262.4831,-212.9494C249.7138,-202.0262 233.3476,-188.0262 220.5685,-177.0947\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- CurrentTerm -->\n",
       "<g class=\"node\" id=\"node10\">\n",
       "<title>CurrentTerm</title>\n",
       "<g id=\"a_node10\"><a xlink:title=\"omega                \r",
       "------------------------------\r",
       "→ Term\r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"329.5,-177 246.5,-177 246.5,-142 329.5,-142 329.5,-177\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"254.5\" y=\"-157.4\">CurrentTerm</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- Term&#45;&gt;CurrentTerm -->\n",
       "<g class=\"edge\" id=\"edge9\">\n",
       "<title>Term-&gt;CurrentTerm</title>\n",
       "<path d=\"M284.236,-212.9494C284.9994,-202.1083 285.9763,-188.2366 286.7435,-177.3418\" fill=\"none\" stroke=\"#000000\" stroke-dasharray=\"5,2\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- Section&#45;&gt;Enroll -->\n",
       "<g class=\"edge\" id=\"edge10\">\n",
       "<title>Section-&gt;Enroll</title>\n",
       "<path d=\"M180.7191,-141.9494C168.7189,-131.0262 153.3387,-117.0262 141.3294,-106.0947\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "</g>\n",
       "</svg>"
      ],
      "text/plain": [
       "<datajoint.diagram.Diagram at 0x7f9b72eb0828>"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "schema.spawn_missing_classes()\n",
    "dj.Di(schema)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Now you may interact with these tables as if they were declared right here in this namespace:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "\n",
       "        \n",
       "        <style type=\"text/css\">\n",
       "            .Relation{\n",
       "                border-collapse:collapse;\n",
       "            }\n",
       "            .Relation th{\n",
       "                background: #A0A0A0; color: #ffffff; padding:4px; border:#f0e0e0 1px solid;\n",
       "                font-weight: normal; font-family: monospace; font-size: 100%;\n",
       "            }\n",
       "            .Relation td{\n",
       "                padding:4px; border:#f0e0e0 1px solid; font-size:100%;\n",
       "            }\n",
       "            .Relation tr:nth-child(odd){\n",
       "                background: #ffffff;\n",
       "            }\n",
       "            .Relation tr:nth-child(even){\n",
       "                background: #f3f1ff;\n",
       "            }\n",
       "            /* Tooltip container */\n",
       "            .djtooltip {\n",
       "            }\n",
       "            /* Tooltip text */\n",
       "            .djtooltip .djtooltiptext {\n",
       "                visibility: hidden;\n",
       "                width: 120px;\n",
       "                background-color: black;\n",
       "                color: #fff;\n",
       "                text-align: center;\n",
       "                padding: 5px 0;\n",
       "                border-radius: 6px;\n",
       "                /* Position the tooltip text - see examples below! */\n",
       "                position: absolute;\n",
       "                z-index: 1;\n",
       "            }\n",
       "            #primary {\n",
       "                font-weight: bold;\n",
       "                color: black;\n",
       "            }\n",
       "\n",
       "            #nonprimary {\n",
       "                font-weight: normal;\n",
       "                color: white;\n",
       "            }\n",
       "\n",
       "            /* Show the tooltip text when you mouse over the tooltip container */\n",
       "            .djtooltip:hover .djtooltiptext {\n",
       "                visibility: visible;\n",
       "            }\n",
       "        </style>\n",
       "        \n",
       "        <b></b>\n",
       "            <div style=\"max-height:1000px;max-width:1500px;overflow:auto;\">\n",
       "            <table border=\"1\" class=\"Relation\">\n",
       "                <thead> <tr style=\"text-align: right;\"> <th> <div class=\"djtooltip\">\n",
       "                                <p id=\"primary\">student_id</p>\n",
       "                                <span class=\"djtooltiptext\">university-wide ID number</span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">first_name</p>\n",
       "                                <span class=\"djtooltiptext\"></span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">last_name</p>\n",
       "                                <span class=\"djtooltiptext\"></span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">sex</p>\n",
       "                                <span class=\"djtooltiptext\"></span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">date_of_birth</p>\n",
       "                                <span class=\"djtooltiptext\"></span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">home_address</p>\n",
       "                                <span class=\"djtooltiptext\">mailing street address</span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">home_city</p>\n",
       "                                <span class=\"djtooltiptext\">mailing address</span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">home_state</p>\n",
       "                                <span class=\"djtooltiptext\">US state acronym: e.g. OH</span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">home_zip</p>\n",
       "                                <span class=\"djtooltiptext\">zipcode e.g. 93979-4979</span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">home_phone</p>\n",
       "                                <span class=\"djtooltiptext\">e.g. 414.657.6883x0881</span>\n",
       "                            </div> </th> </tr> </thead>\n",
       "                <tbody> <tr> <td>1003</td>\n",
       "<td>Jonathan</td>\n",
       "<td>Wilson</td>\n",
       "<td>M</td>\n",
       "<td>2002-10-19</td>\n",
       "<td>91101 Summer Park</td>\n",
       "<td>Port Jacqueline</td>\n",
       "<td>VT</td>\n",
       "<td>75616</td>\n",
       "<td>982.251.1567x21450</td></tr><tr><td>1005</td>\n",
       "<td>Richard</td>\n",
       "<td>Lopez</td>\n",
       "<td>M</td>\n",
       "<td>1993-10-16</td>\n",
       "<td>86210 Brooks Station</td>\n",
       "<td>West David</td>\n",
       "<td>IL</td>\n",
       "<td>96184</td>\n",
       "<td>+1-385-481-6761x1575</td></tr><tr><td>1006</td>\n",
       "<td>Laura</td>\n",
       "<td>Hammond</td>\n",
       "<td>F</td>\n",
       "<td>1984-12-03</td>\n",
       "<td>0346 Shannon Motorway</td>\n",
       "<td>East David</td>\n",
       "<td>ME</td>\n",
       "<td>22113</td>\n",
       "<td>(189)406-2652x143</td> </tr> </tbody>\n",
       "            </table>\n",
       "            <p>...</p>\n",
       "            <p>Total: 751</p></div>\n",
       "            "
      ],
      "text/plain": [
       "*student_id    first_name     last_name     sex     date_of_birth  home_address   home_city      home_state     home_zip     home_phone    \n",
       "+------------+ +------------+ +-----------+ +-----+ +------------+ +------------+ +------------+ +------------+ +----------+ +------------+\n",
       "1003           Jonathan       Wilson        M       2002-10-19     91101 Summer P Port Jacquelin VT             75616        982.251.1567x2\n",
       "1005           Richard        Lopez         M       1993-10-16     86210 Brooks S West David     IL             96184        +1-385-481-676\n",
       "1006           Laura          Hammond       F       1984-12-03     0346 Shannon M East David     ME             22113        (189)406-2652x\n",
       "   ...\n",
       " (Total: 751)"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# students without majors \n",
    "Student - StudentMajor"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### <font color=\"green\">**!!! Restart the kernel here to remove the previous class definitions !!!**</font>\n",
    "\n",
    "# Creating a virtual module\n",
    "Now `spawn_missing_classes` creates the new classes in the local namespace. However, it is often more convenient to import a schema with its python module, equivalent to the python the python command \n",
    "```python\n",
    "import university as uni\n",
    "```\n",
    "\n",
    "We can mimick this import without having access to `university.py` using the `create_virtual_module` function:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Connecting dimitri@localhost:3306\n"
     ]
    }
   ],
   "source": [
    "import datajoint as dj\n",
    "\n",
    "uni = dj.create_virtual_module('university', 'dimitri_university')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Now `uni` behaves as an imported module complete with the `schema` object and all the table classes."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "image/svg+xml": [
       "<svg height=\"327pt\" viewBox=\"0.00 0.00 403.50 327.00\" width=\"404pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">\n",
       "<g class=\"graph\" id=\"graph0\" transform=\"scale(1 1) rotate(0) translate(4 323)\">\n",
       "<title>%3</title>\n",
       "<polygon fill=\"#ffffff\" points=\"-4,4 -4,-323 399.5,-323 399.5,4 -4,4\" stroke=\"transparent\"/>\n",
       "<!-- uni.CurrentTerm -->\n",
       "<g class=\"node\" id=\"node1\">\n",
       "<title>uni.CurrentTerm</title>\n",
       "<g id=\"a_node1\"><a xlink:title=\"omega                \r",
       "------------------------------\r",
       "→ uni.Term\r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"102,-177 0,-177 0,-142 102,-142 102,-177\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"8\" y=\"-157.4\">uni.CurrentTerm</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Section -->\n",
       "<g class=\"node\" id=\"node2\">\n",
       "<title>uni.Section</title>\n",
       "<g id=\"a_node2\"><a xlink:title=\"→ uni.Course\r",
       "→ uni.Term\r",
       "section              \r",
       "------------------------------\r",
       "auditorium           \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"197.5,-177 120.5,-177 120.5,-142 197.5,-142 197.5,-177\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"128.5\" y=\"-157.4\">uni.Section</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Enroll -->\n",
       "<g class=\"node\" id=\"node4\">\n",
       "<title>uni.Enroll</title>\n",
       "<g id=\"a_node4\"><a xlink:title=\"→ uni.Student\r",
       "→ uni.Section\r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"278,-106 210,-106 210,-71 278,-71 278,-106\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"middle\" x=\"244\" y=\"-85.4\">uni.Enroll</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Section&#45;&gt;uni.Enroll -->\n",
       "<g class=\"edge\" id=\"edge1\">\n",
       "<title>uni.Section-&gt;uni.Enroll</title>\n",
       "<path d=\"M180.0112,-141.9494C193.0883,-131.0262 209.8489,-117.0262 222.9359,-106.0947\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.Grade -->\n",
       "<g class=\"node\" id=\"node3\">\n",
       "<title>uni.Grade</title>\n",
       "<g id=\"a_node3\"><a xlink:title=\"→ uni.Enroll\r",
       "------------------------------\r",
       "→ uni.LetterGrade\r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"329.5,-35 260.5,-35 260.5,0 329.5,0 329.5,-35\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"middle\" x=\"295\" y=\"-14.4\">uni.Grade</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Enroll&#45;&gt;uni.Grade -->\n",
       "<g class=\"edge\" id=\"edge2\">\n",
       "<title>uni.Enroll-&gt;uni.Grade</title>\n",
       "<path d=\"M256.6067,-70.9494C264.394,-60.1083 274.3582,-46.2366 282.184,-35.3418\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\"2\"/>\n",
       "</g>\n",
       "<!-- uni.StudentMajor -->\n",
       "<g class=\"node\" id=\"node5\">\n",
       "<title>uni.StudentMajor</title>\n",
       "<g id=\"a_node5\"><a xlink:title=\"→ uni.Student\r",
       "------------------------------\r",
       "→ uni.Department\r",
       "declare_date         \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"315.5,-248 208.5,-248 208.5,-213 315.5,-213 315.5,-248\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"middle\" x=\"262\" y=\"-227.4\">uni.StudentMajor</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Department -->\n",
       "<g class=\"node\" id=\"node6\">\n",
       "<title>uni.Department</title>\n",
       "<g id=\"a_node6\"><a xlink:title=\"dept                 \r",
       "------------------------------\r",
       "dept_name            \r",
       "dept_address         \r",
       "dept_phone           \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"245,-319 147,-319 147,-284 245,-284 245,-319\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"155\" y=\"-299.4\">uni.Department</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Department&#45;&gt;uni.StudentMajor -->\n",
       "<g class=\"edge\" id=\"edge3\">\n",
       "<title>uni.Department-&gt;uni.StudentMajor</title>\n",
       "<path d=\"M212.3146,-283.9494C222.3922,-273.1083 235.2871,-259.2366 245.4146,-248.3418\" fill=\"none\" stroke=\"#000000\" stroke-dasharray=\"5,2\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.Course -->\n",
       "<g class=\"node\" id=\"node7\">\n",
       "<title>uni.Course</title>\n",
       "<g id=\"a_node7\"><a xlink:title=\"→ uni.Department\r",
       "course               \r",
       "------------------------------\r",
       "course_name          \r",
       "credits              \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"190.5,-248 115.5,-248 115.5,-213 190.5,-213 190.5,-248\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"123.5\" y=\"-228.4\">uni.Course</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Department&#45;&gt;uni.Course -->\n",
       "<g class=\"edge\" id=\"edge4\">\n",
       "<title>uni.Department-&gt;uni.Course</title>\n",
       "<path d=\"M185.3708,-283.9494C178.8051,-273.1083 170.4038,-259.2366 163.8056,-248.3418\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.Course&#45;&gt;uni.Section -->\n",
       "<g class=\"edge\" id=\"edge5\">\n",
       "<title>uni.Course-&gt;uni.Section</title>\n",
       "<path d=\"M154.4831,-212.9494C155.3993,-202.1083 156.5716,-188.2366 157.4922,-177.3418\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.Student -->\n",
       "<g class=\"node\" id=\"node8\">\n",
       "<title>uni.Student</title>\n",
       "<g id=\"a_node8\"><a xlink:title=\"student_id           \r",
       "------------------------------\r",
       "first_name           \r",
       "last_name            \r",
       "sex                  \r",
       "date_of_birth        \r",
       "home_address         \r",
       "home_city            \r",
       "home_state           \r",
       "home_zip             \r",
       "home_phone           \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"341.5,-319 264.5,-319 264.5,-284 341.5,-284 341.5,-319\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"272.5\" y=\"-299.4\">uni.Student</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Student&#45;&gt;uni.Enroll -->\n",
       "<g class=\"edge\" id=\"edge6\">\n",
       "<title>uni.Student-&gt;uni.Enroll</title>\n",
       "<path d=\"M313.0004,-283.7434C321.8098,-265.7843 332.2047,-237.2853 325,-213 312.3853,-170.479 280.1569,-128.8943 260.3652,-106.1824\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.Student&#45;&gt;uni.StudentMajor -->\n",
       "<g class=\"edge\" id=\"edge7\">\n",
       "<title>uni.Student-&gt;uni.StudentMajor</title>\n",
       "<path d=\"M292.8652,-283.9494C286.6048,-273.1083 278.5944,-259.2366 272.303,-248.3418\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\"2\"/>\n",
       "</g>\n",
       "<!-- uni.Term -->\n",
       "<g class=\"node\" id=\"node9\">\n",
       "<title>uni.Term</title>\n",
       "<g id=\"a_node9\"><a xlink:title=\"term_year            \r",
       "term                 \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"92,-248 30,-248 30,-213 92,-213 92,-248\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"38\" y=\"-228.4\">uni.Term</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Term&#45;&gt;uni.CurrentTerm -->\n",
       "<g class=\"edge\" id=\"edge8\">\n",
       "<title>uni.Term-&gt;uni.CurrentTerm</title>\n",
       "<path d=\"M58.5281,-212.9494C57.0012,-202.1083 55.0474,-188.2366 53.5129,-177.3418\" fill=\"none\" stroke=\"#000000\" stroke-dasharray=\"5,2\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.Term&#45;&gt;uni.Section -->\n",
       "<g class=\"edge\" id=\"edge9\">\n",
       "<title>uni.Term-&gt;uni.Section</title>\n",
       "<path d=\"M85.2247,-212.9494C100.3018,-202.0262 119.6258,-188.0262 134.7143,-177.0947\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.LetterGrade -->\n",
       "<g class=\"node\" id=\"node10\">\n",
       "<title>uni.LetterGrade</title>\n",
       "<g id=\"a_node10\"><a xlink:title=\"grade                \r",
       "------------------------------\r",
       "points               \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"395.5,-106 296.5,-106 296.5,-71 395.5,-71 395.5,-106\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"304.5\" y=\"-86.4\">uni.LetterGrade</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.LetterGrade&#45;&gt;uni.Grade -->\n",
       "<g class=\"edge\" id=\"edge10\">\n",
       "<title>uni.LetterGrade-&gt;uni.Grade</title>\n",
       "<path d=\"M333.3933,-70.9494C325.606,-60.1083 315.6418,-46.2366 307.816,-35.3418\" fill=\"none\" stroke=\"#000000\" stroke-dasharray=\"5,2\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "</g>\n",
       "</svg>"
      ],
      "text/plain": [
       "<datajoint.diagram.Diagram at 0x7fd43e72fb00>"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "dj.Di(uni)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "\n",
       "        \n",
       "        <style type=\"text/css\">\n",
       "            .Relation{\n",
       "                border-collapse:collapse;\n",
       "            }\n",
       "            .Relation th{\n",
       "                background: #A0A0A0; color: #ffffff; padding:4px; border:#f0e0e0 1px solid;\n",
       "                font-weight: normal; font-family: monospace; font-size: 100%;\n",
       "            }\n",
       "            .Relation td{\n",
       "                padding:4px; border:#f0e0e0 1px solid; font-size:100%;\n",
       "            }\n",
       "            .Relation tr:nth-child(odd){\n",
       "                background: #ffffff;\n",
       "            }\n",
       "            .Relation tr:nth-child(even){\n",
       "                background: #f3f1ff;\n",
       "            }\n",
       "            /* Tooltip container */\n",
       "            .djtooltip {\n",
       "            }\n",
       "            /* Tooltip text */\n",
       "            .djtooltip .djtooltiptext {\n",
       "                visibility: hidden;\n",
       "                width: 120px;\n",
       "                background-color: black;\n",
       "                color: #fff;\n",
       "                text-align: center;\n",
       "                padding: 5px 0;\n",
       "                border-radius: 6px;\n",
       "                /* Position the tooltip text - see examples below! */\n",
       "                position: absolute;\n",
       "                z-index: 1;\n",
       "            }\n",
       "            #primary {\n",
       "                font-weight: bold;\n",
       "                color: black;\n",
       "            }\n",
       "\n",
       "            #nonprimary {\n",
       "                font-weight: normal;\n",
       "                color: white;\n",
       "            }\n",
       "\n",
       "            /* Show the tooltip text when you mouse over the tooltip container */\n",
       "            .djtooltip:hover .djtooltiptext {\n",
       "                visibility: visible;\n",
       "            }\n",
       "        </style>\n",
       "        \n",
       "        <b></b>\n",
       "            <div style=\"max-height:1000px;max-width:1500px;overflow:auto;\">\n",
       "            <table border=\"1\" class=\"Relation\">\n",
       "                <thead> <tr style=\"text-align: right;\"> <th> <div class=\"djtooltip\">\n",
       "                                <p id=\"primary\">student_id</p>\n",
       "                                <span class=\"djtooltiptext\">university-wide ID number</span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">first_name</p>\n",
       "                                <span class=\"djtooltiptext\"></span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">last_name</p>\n",
       "                                <span class=\"djtooltiptext\"></span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">sex</p>\n",
       "                                <span class=\"djtooltiptext\"></span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">date_of_birth</p>\n",
       "                                <span class=\"djtooltiptext\"></span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">home_address</p>\n",
       "                                <span class=\"djtooltiptext\">mailing street address</span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">home_city</p>\n",
       "                                <span class=\"djtooltiptext\">mailing address</span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">home_state</p>\n",
       "                                <span class=\"djtooltiptext\">US state acronym: e.g. OH</span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">home_zip</p>\n",
       "                                <span class=\"djtooltiptext\">zipcode e.g. 93979-4979</span>\n",
       "                            </div></th><th><div class=\"djtooltip\">\n",
       "                                <p id=\"nonprimary\">home_phone</p>\n",
       "                                <span class=\"djtooltiptext\">e.g. 414.657.6883x0881</span>\n",
       "                            </div> </th> </tr> </thead>\n",
       "                <tbody> <tr> <td>1003</td>\n",
       "<td>Jonathan</td>\n",
       "<td>Wilson</td>\n",
       "<td>M</td>\n",
       "<td>2002-10-19</td>\n",
       "<td>91101 Summer Park</td>\n",
       "<td>Port Jacqueline</td>\n",
       "<td>VT</td>\n",
       "<td>75616</td>\n",
       "<td>982.251.1567x21450</td></tr><tr><td>1005</td>\n",
       "<td>Richard</td>\n",
       "<td>Lopez</td>\n",
       "<td>M</td>\n",
       "<td>1993-10-16</td>\n",
       "<td>86210 Brooks Station</td>\n",
       "<td>West David</td>\n",
       "<td>IL</td>\n",
       "<td>96184</td>\n",
       "<td>+1-385-481-6761x1575</td></tr><tr><td>1006</td>\n",
       "<td>Laura</td>\n",
       "<td>Hammond</td>\n",
       "<td>F</td>\n",
       "<td>1984-12-03</td>\n",
       "<td>0346 Shannon Motorway</td>\n",
       "<td>East David</td>\n",
       "<td>ME</td>\n",
       "<td>22113</td>\n",
       "<td>(189)406-2652x143</td> </tr> </tbody>\n",
       "            </table>\n",
       "            <p>...</p>\n",
       "            <p>Total: 751</p></div>\n",
       "            "
      ],
      "text/plain": [
       "*student_id    first_name     last_name     sex     date_of_birth  home_address   home_city      home_state     home_zip     home_phone    \n",
       "+------------+ +------------+ +-----------+ +-----+ +------------+ +------------+ +------------+ +------------+ +----------+ +------------+\n",
       "1003           Jonathan       Wilson        M       2002-10-19     91101 Summer P Port Jacquelin VT             75616        982.251.1567x2\n",
       "1005           Richard        Lopez         M       1993-10-16     86210 Brooks S West David     IL             96184        +1-385-481-676\n",
       "1006           Laura          Hammond       F       1984-12-03     0346 Shannon M East David     ME             22113        (189)406-2652x\n",
       "   ...\n",
       " (Total: 751)"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "uni.Student - uni.StudentMajor"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "`dj.create_virtual_module` takes optional arguments. \n",
    "\n",
    "First, `create_schema=False` assures that an error is raised when the schema does not already exist. Set it to `True` if you want to create an empty schema."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "ename": "DataJointError",
     "evalue": "Database named `nonexistent` was not defined. Set argument create_schema=True to create it.",
     "output_type": "error",
     "traceback": [
      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[0;31mDataJointError\u001b[0m                            Traceback (most recent call last)",
      "\u001b[0;32m<ipython-input-4-b316110c06f3>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0mdj\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mcreate_virtual_module\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m'what'\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0;34m'nonexistent'\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[0;32m~/dev/datajoint-python/datajoint/schema.py\u001b[0m in \u001b[0;36mcreate_virtual_module\u001b[0;34m(module_name, schema_name, create_schema, create_tables, connection)\u001b[0m\n\u001b[1;32m    242\u001b[0m     \"\"\"\n\u001b[1;32m    243\u001b[0m     \u001b[0mmodule\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mtypes\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mModuleType\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mmodule_name\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m--> 244\u001b[0;31m     \u001b[0m_schema\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mSchema\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mschema_name\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mcreate_schema\u001b[0m\u001b[0;34m=\u001b[0m\u001b[0mcreate_schema\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mcreate_tables\u001b[0m\u001b[0;34m=\u001b[0m\u001b[0mcreate_tables\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mconnection\u001b[0m\u001b[0;34m=\u001b[0m\u001b[0mconnection\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m    245\u001b[0m     \u001b[0m_schema\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mspawn_missing_classes\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mcontext\u001b[0m\u001b[0;34m=\u001b[0m\u001b[0mmodule\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0m__dict__\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m    246\u001b[0m     \u001b[0mmodule\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0m__dict__\u001b[0m\u001b[0;34m[\u001b[0m\u001b[0;34m'schema'\u001b[0m\u001b[0;34m]\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0m_schema\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
      "\u001b[0;32m~/dev/datajoint-python/datajoint/schema.py\u001b[0m in \u001b[0;36m__init__\u001b[0;34m(self, schema_name, context, connection, create_schema, create_tables)\u001b[0m\n\u001b[1;32m     65\u001b[0m                 raise DataJointError(\n\u001b[1;32m     66\u001b[0m                     \u001b[0;34m\"Database named `{name}` was not defined. \"\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m---> 67\u001b[0;31m                     \"Set argument create_schema=True to create it.\".format(name=schema_name))\n\u001b[0m\u001b[1;32m     68\u001b[0m             \u001b[0;32melse\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m     69\u001b[0m                 \u001b[0;31m# create database\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
      "\u001b[0;31mDataJointError\u001b[0m: Database named `nonexistent` was not defined. Set argument create_schema=True to create it."
     ]
    }
   ],
   "source": [
    "dj.create_virtual_module('what', 'nonexistent')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The other optional argument, `create_tables=False` is passed to the `schema` object. It prevents the use of the `schema` obect of the virtual module for creating new tables in the existing schema. This is a precautionary measure since virtual modules are often used for completed schemas. You may set this argument to `True` if you wish to add new tables to the existing schema. A more common approach in this scenario would be to create a new `schema` object and to use the `spawn_missing_classes` function to make the classes available.\n",
    "\n",
    "However, you if do decide to create new tables in an existing tables using the virtual module, you may do so by using the schema object from the module as the decorator for declaring new tables:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [],
   "source": [
    "uni = dj.create_virtual_module('university.py', 'dimitri_university', create_tables=True)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [],
   "source": [
    "@uni.schema\n",
    "class Example(dj.Manual):\n",
    "    definition = \"\"\"\n",
    "    -> uni.Student \n",
    "    ---\n",
    "    example : varchar(255)\n",
    "    \"\"\""
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "image/svg+xml": [
       "<svg height=\"327pt\" viewBox=\"0.00 0.00 444.50 327.00\" width=\"445pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\">\n",
       "<g class=\"graph\" id=\"graph0\" transform=\"scale(1 1) rotate(0) translate(4 323)\">\n",
       "<title>%3</title>\n",
       "<polygon fill=\"#ffffff\" points=\"-4,4 -4,-323 440.5,-323 440.5,4 -4,4\" stroke=\"transparent\"/>\n",
       "<!-- uni.CurrentTerm -->\n",
       "<g class=\"node\" id=\"node1\">\n",
       "<title>uni.CurrentTerm</title>\n",
       "<g id=\"a_node1\"><a xlink:title=\"omega                \r",
       "------------------------------\r",
       "→ uni.Term\r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"102,-177 0,-177 0,-142 102,-142 102,-177\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"8\" y=\"-157.4\">uni.CurrentTerm</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Term -->\n",
       "<g class=\"node\" id=\"node2\">\n",
       "<title>uni.Term</title>\n",
       "<g id=\"a_node2\"><a xlink:title=\"term_year            \r",
       "term                 \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"92,-248 30,-248 30,-213 92,-213 92,-248\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"38\" y=\"-228.4\">uni.Term</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Term&#45;&gt;uni.CurrentTerm -->\n",
       "<g class=\"edge\" id=\"edge1\">\n",
       "<title>uni.Term-&gt;uni.CurrentTerm</title>\n",
       "<path d=\"M58.5281,-212.9494C57.0012,-202.1083 55.0474,-188.2366 53.5129,-177.3418\" fill=\"none\" stroke=\"#000000\" stroke-dasharray=\"5,2\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.Section -->\n",
       "<g class=\"node\" id=\"node3\">\n",
       "<title>uni.Section</title>\n",
       "<g id=\"a_node3\"><a xlink:title=\"→ uni.Course\r",
       "→ uni.Term\r",
       "section              \r",
       "------------------------------\r",
       "auditorium           \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"197.5,-177 120.5,-177 120.5,-142 197.5,-142 197.5,-177\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"128.5\" y=\"-157.4\">uni.Section</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Term&#45;&gt;uni.Section -->\n",
       "<g class=\"edge\" id=\"edge2\">\n",
       "<title>uni.Term-&gt;uni.Section</title>\n",
       "<path d=\"M85.2247,-212.9494C100.3018,-202.0262 119.6258,-188.0262 134.7143,-177.0947\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.Enroll -->\n",
       "<g class=\"node\" id=\"node5\">\n",
       "<title>uni.Enroll</title>\n",
       "<g id=\"a_node5\"><a xlink:title=\"→ uni.Student\r",
       "→ uni.Section\r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"319,-106 251,-106 251,-71 319,-71 319,-106\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"middle\" x=\"285\" y=\"-85.4\">uni.Enroll</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Section&#45;&gt;uni.Enroll -->\n",
       "<g class=\"edge\" id=\"edge3\">\n",
       "<title>uni.Section-&gt;uni.Enroll</title>\n",
       "<path d=\"M190.1461,-141.9494C209.5309,-131.0262 234.376,-117.0262 253.7755,-106.0947\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.Grade -->\n",
       "<g class=\"node\" id=\"node4\">\n",
       "<title>uni.Grade</title>\n",
       "<g id=\"a_node4\"><a xlink:title=\"→ uni.Enroll\r",
       "------------------------------\r",
       "→ uni.LetterGrade\r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"370.5,-35 301.5,-35 301.5,0 370.5,0 370.5,-35\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"middle\" x=\"336\" y=\"-14.4\">uni.Grade</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Enroll&#45;&gt;uni.Grade -->\n",
       "<g class=\"edge\" id=\"edge4\">\n",
       "<title>uni.Enroll-&gt;uni.Grade</title>\n",
       "<path d=\"M297.6067,-70.9494C305.394,-60.1083 315.3582,-46.2366 323.184,-35.3418\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\"2\"/>\n",
       "</g>\n",
       "<!-- uni.StudentMajor -->\n",
       "<g class=\"node\" id=\"node6\">\n",
       "<title>uni.StudentMajor</title>\n",
       "<g id=\"a_node6\"><a xlink:title=\"→ uni.Student\r",
       "------------------------------\r",
       "→ uni.Department\r",
       "declare_date         \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"315.5,-248 208.5,-248 208.5,-213 315.5,-213 315.5,-248\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"middle\" x=\"262\" y=\"-227.4\">uni.StudentMajor</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Department -->\n",
       "<g class=\"node\" id=\"node7\">\n",
       "<title>uni.Department</title>\n",
       "<g id=\"a_node7\"><a xlink:title=\"dept                 \r",
       "------------------------------\r",
       "dept_name            \r",
       "dept_address         \r",
       "dept_phone           \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"256,-319 158,-319 158,-284 256,-284 256,-319\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"166\" y=\"-299.4\">uni.Department</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Department&#45;&gt;uni.StudentMajor -->\n",
       "<g class=\"edge\" id=\"edge5\">\n",
       "<title>uni.Department-&gt;uni.StudentMajor</title>\n",
       "<path d=\"M220.5955,-283.9494C228.9935,-273.1083 239.7393,-259.2366 248.1789,-248.3418\" fill=\"none\" stroke=\"#000000\" stroke-dasharray=\"5,2\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.Course -->\n",
       "<g class=\"node\" id=\"node8\">\n",
       "<title>uni.Course</title>\n",
       "<g id=\"a_node8\"><a xlink:title=\"→ uni.Department\r",
       "course               \r",
       "------------------------------\r",
       "course_name          \r",
       "credits              \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"190.5,-248 115.5,-248 115.5,-213 190.5,-213 190.5,-248\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"123.5\" y=\"-228.4\">uni.Course</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Department&#45;&gt;uni.Course -->\n",
       "<g class=\"edge\" id=\"edge6\">\n",
       "<title>uni.Department-&gt;uni.Course</title>\n",
       "<path d=\"M193.6517,-283.9494C185.4064,-273.1083 174.856,-259.2366 166.5698,-248.3418\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.Course&#45;&gt;uni.Section -->\n",
       "<g class=\"edge\" id=\"edge7\">\n",
       "<title>uni.Course-&gt;uni.Section</title>\n",
       "<path d=\"M154.4831,-212.9494C155.3993,-202.1083 156.5716,-188.2366 157.4922,-177.3418\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.Student -->\n",
       "<g class=\"node\" id=\"node9\">\n",
       "<title>uni.Student</title>\n",
       "<g id=\"a_node9\"><a xlink:title=\"student_id           \r",
       "------------------------------\r",
       "first_name           \r",
       "last_name            \r",
       "sex                  \r",
       "date_of_birth        \r",
       "home_address         \r",
       "home_city            \r",
       "home_state           \r",
       "home_zip             \r",
       "home_phone           \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"404.5,-319 327.5,-319 327.5,-284 404.5,-284 404.5,-319\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"335.5\" y=\"-299.4\">uni.Student</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Student&#45;&gt;uni.Enroll -->\n",
       "<g class=\"edge\" id=\"edge8\">\n",
       "<title>uni.Student-&gt;uni.Enroll</title>\n",
       "<path d=\"M384.1718,-283.9836C392.8886,-274.3045 402.4151,-261.5202 407,-248 411.9957,-233.2684 412.8799,-227.4015 407,-213 387.8398,-166.0714 341.5237,-127.2543 311.7904,-106.0243\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "<!-- uni.Student&#45;&gt;uni.StudentMajor -->\n",
       "<g class=\"edge\" id=\"edge9\">\n",
       "<title>uni.Student-&gt;uni.StudentMajor</title>\n",
       "<path d=\"M340.2921,-283.9494C324.2919,-273.0262 303.7849,-259.0262 287.7726,-248.0947\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\"2\"/>\n",
       "</g>\n",
       "<!-- Example -->\n",
       "<g class=\"node\" id=\"node10\">\n",
       "<title>Example</title>\n",
       "<g id=\"a_node10\"><a xlink:title=\"→ uni.Student\r",
       "------------------------------\r",
       "example              \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"398,-248 334,-248 334,-213 398,-213 398,-248\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"middle\" x=\"366\" y=\"-227.4\">Example</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.Student&#45;&gt;Example -->\n",
       "<g class=\"edge\" id=\"edge10\">\n",
       "<title>uni.Student-&gt;Example</title>\n",
       "<path d=\"M366,-283.9494C366,-273.1083 366,-259.2366 366,-248.3418\" fill=\"none\" stroke=\"#000000\" stroke-opacity=\"0.250980\" stroke-width=\"2\"/>\n",
       "</g>\n",
       "<!-- uni.LetterGrade -->\n",
       "<g class=\"node\" id=\"node11\">\n",
       "<title>uni.LetterGrade</title>\n",
       "<g id=\"a_node11\"><a xlink:title=\"grade                \r",
       "------------------------------\r",
       "points               \r",
       "\">\n",
       "<polygon fill=\"#00ff00\" fill-opacity=\"0.188235\" points=\"436.5,-106 337.5,-106 337.5,-71 436.5,-71 436.5,-106\" stroke=\"#00ff00\" stroke-opacity=\"0.188235\"/>\n",
       "<text fill=\"#006400\" font-family=\"arial\" font-size=\"12.00\" text-anchor=\"start\" text-decoration=\"underline\" x=\"345.5\" y=\"-86.4\">uni.LetterGrade</text>\n",
       "</a>\n",
       "</g>\n",
       "</g>\n",
       "<!-- uni.LetterGrade&#45;&gt;uni.Grade -->\n",
       "<g class=\"edge\" id=\"edge11\">\n",
       "<title>uni.LetterGrade-&gt;uni.Grade</title>\n",
       "<path d=\"M374.3933,-70.9494C366.606,-60.1083 356.6418,-46.2366 348.816,-35.3418\" fill=\"none\" stroke=\"#000000\" stroke-dasharray=\"5,2\" stroke-opacity=\"0.250980\" stroke-width=\".75\"/>\n",
       "</g>\n",
       "</g>\n",
       "</svg>"
      ],
      "text/plain": [
       "<datajoint.diagram.Diagram at 0x7fd43e369278>"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "dj.Di(uni)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "-> uni.Student\n",
      "-> uni.Section\n",
      "\n"
     ]
    }
   ],
   "source": [
    "uni.Enroll.describe();"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "uni.save()"
   ]
  }
 ],
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   "display_name": "Python 3",
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