Refactoring/#294 refactor column name type

[ckunki]

Closes #294
Closes #292

[ckunki]

Diff is quite large for this file.

[ahsimb]

A general comment. The column.py is now mostly about the column type. Would you like to create a separate file column_type.py and move the type classes there? Also, I think naming should change. For example the VarcharColumn should be renamed to VarcharColumnType or VarcharType.

[ckunki]

A general comment. The column.py is now mostly about the column type. Would you like to create a separate file column_type.py and move the type classes there? Also, I think naming should change. For example the VarcharColumn should be renamed to VarcharColumnType or VarcharType.

Thanks for this comment.

I needed to put class ColumnType and subclasses and top level class Column into one file to calm down mypy.

Reason is that each subclass still (and again) contains a class method simple() which now does not create an instance of a ColumnType but of Column. I find this convenient from a user's perspective. But I agree that this might not be 100% clean from a typing perspective.

This also is a reason for not naming the subclasses VarCharColumnType or VarCharType but VarCharColumn, see the examples in the user guide which read nicely, I hope.

However if you prefer then I can also replace methods simple() from the subclasses of ColumnType by top-level functions, eg. varchar_column().

This would then enable

• splitting up the file into column.py and column_type.py
• renaming the subclasses of ColumnType to VarCharColumnType or VarCharType

[ahsimb]

I didn't notice first that the simple still creates a Column. It looks really weird when A contains B, but B can create A. I would strongly suggest that the column type minds its own business. So for example it can theoretically be used in something like MyFancyColumn which is not derived from Column.

[tkilias]

if the super type is ColumType, I am not sure if BooleanColumn is an appropriate name , some for the other ones

[tkilias]

would SQLType maybe more correct?

[ckunki]

Not too bad in my eyes. I only already have a class SqlType in column_type_utils.py already, that should be renamed then.

[ckunki]

Compared to the last commit, the classes in this file have been moved from column.py.