Entities

D3 ORM it's all about entities. In D3 - entity is a structure with an identifier. All entities have fields and methods, in other words, has state and behavior.

You may create any methods you want. Supported field types:

• bool, sql.NullBool
• int, int32, int64, sql.NullInt32, sql.NullInt64
• float32, float64, sql.NullFloat64
• string, sql.NullString
• time.Time, sql.NullTime
• any type defined from above
• github.com/gofrs/uuid.UUID
• *Collection and *Cell (explained below in Relations section)

Primary keys

As said above all entities must have an identifier. In d3 identifier named primary key. For mark struct field as primary key use d3:"pk:< type >" tag. Available pk types:

• auto - auto-generated value. The key field type must be one of sql.NullInt32 or sql.NullInt64.
• manual - key will be set manually, by a developer.

Example

import	"github.com/gofrs/uuid"

//d3:entity
//d3_table:user
type User struct {
    id             sql.NullInt32 `d3:"pk:auto"`
    name           string             
    lastSeenAt     time.Time
    isAdmin        bool
}

type Email string

//d3:entity
//d3_index_unique:user_idx(email)
type User2 struct {
    id      uuid.UUID `d3:"pk:manual"`
    email   Email             
}

Mapping

Tags and comments provided by D3:

Comment	Required	Value	Explanation	Example
d3:entity	yes		mark structure as D3 entity	//d3:entity
d3_table:...	no	name of table	sets table for persists entity data	//d3_table:user
d3_index:...	no	name and fields of index	create index for entity table	//d3_index:book_name_idx(name)
d3_index_unique:...	no	name and fields of index	create unique index for entity table	//d3_index_unique:book_isbn_idx(isbn)

Tag	Required	Value	Explanation	Example
pk	yes	auto/manual	marks field used by D3 as entity identify	d3:"pk:auto"
column	no	db column name	map structure scalar field to a database column, by default D3 map structure field to column with the same name as a field in snake_case	d3:"column:name"
one_to_one	no	D3 configuration subtag	configuration for one to one relation, look more at relation page	d3:"one_to_one:<target_entity:User, join_on:t2_id>"
one_to_many	no	D3 configuration subtag	configuration for one to many relation, look more at relation page	d3:"one_to_many: <target_entity:Book, join_on:t1_id>"
many_to_many	no	D3 configuration subtag	configuration for many to many relation, look more at relation page	d3:"many_to_many: <target_entity:Author, join_on:book_id, reference_on:author_id,join_table:book_author>"
type	no	lazy/eager	type of relation, lazy by default	d3:"type:eager"