fix generated boolean default value in mssql

[szro0]

Hi Levente,

I have created a possible fix for a bug or not-yet-implemented feature.

Issue: When a Python class contains a boolean field with a default value, e.g. boolean_false: bool = False or nullable_boolean_true: Optional[bool] = True then the CREATE TABLE statement generated by pysqlsync for MSSQL contains an invalid syntax:

• Before:
  • "boolean_false" bit NOT NULL CONSTRAINT "df_boolean_false" DEFAULT FALSE -- invalid in MSSQL
  • "nullable_boolean_true" bit CONSTRAINT "df_nullable_boolean_true" DEFAULT TRUE -- invalid in MSSQL
• After my fix:
  • "boolean_false" bit NOT NULL CONSTRAINT "df_boolean_false" DEFAULT 0 -- valid in MSSQL
  • "nullable_boolean_true" bit CONSTRAINT "df_nullable_boolean_true" DEFAULT 1 -- valid in MSSQL

Other dialects (PostgreSQL etc) are fine.

The implementation I created is my best effort understanding and extending the code base, please advise how it could be made even better.

Thanks, Robert

[hunyadi]

Thanks for identifying this bug with Boolean default values in Microsoft SQL Server! I did not spot any deal-breaker issues, I am happy to merge tomorrow. Nonetheless, I have proposed some suggestions to make the code easier to read, and better convey the developer's intent.

[hunyadi]

Thanks for the updates! Drop me a message if you need a new version released to PyPI with the changes included.

[hunyadi]

A more elegant approach to this problem is to test for valid type first:

if not isinstance(value, bool):
    raise TypeError(f"expected: value of type `bool`, got: {type(value)}")

This allows type checkers to infer that value is either True or False in subsequent code (the only allowed values for type bool).

[szro0]

Cool thanks, done.

[szro0]

Thank you very much Levente, I'm still testing some use cases, I'll let you know when you can go ahead with the pypi release.

[szro0]

@hunyadi, I found an issue still in MSSQL; the DEFAULT-constraint-name is not table-specific which prevents the creation of multiple tables with the same column-name and those columns having default values. I'm looking for a possible solution. Please don't release a new PyPI version until this gets resolved.