support **kwargs for Column / add_column() / autogenerate

[sqlalchemy-bot]

Migrated issue, originally created by Michael Bayer (@zzzeek)

In SQLAlchemy zzzeek/sqlalchemy@de804d7245d we added support for **kwargs in Column. op.alter_column() needs to support these and they should also autogen render in the same way as options for CreateIndexOp. The immediate need is for redshift-sqlalchemy to make use of this, as they use info now https://github.com/sqlalchemy-redshift/sqlalchemy-redshift/blob/master/sqlalchemy_redshift/dialect.py#L238 but .info is too open-ended to render within autogenerate.

[ParthS007]

@zzzeek @mikeywaites I want to work on this issue. How should I proceed?

[zzzeek]

for this one, we want add_column() (not alter_column, I think that's wrong) to support **kwargs. So I can put any key=value in add_column(). then these **kwargs would need to be propagated over to here: https://github.com/sqlalchemy/sqlalchemy/blob/master/lib/sqlalchemy/sql/schema.py#L1355 .

so it's adding the **kwargs, and also when we autogenereate op.create_table() or op.add_column(), those kwargs from the Column object need to render in the Python code.

So this issue requires some knowledge of autogenerate and such to implement. definitely doable but if you haven't worked w/ autogenerate it might take awhlie to familiarize.

[ParthS007]

okay @zzzeek , I will look into it. Is there any other issue which will be doable for me, you can provide the link to issues and I will go through them. Thanks for the help. :)

[ms32035]

@zzzeek, as discussed in Bitbucket, I submitted a PR to support this functionality for Redshift. sqlalchemy-redshift/sqlalchemy-redshift#161
Since Redshift does not support ALTER for columns it's only generation

[zzzeek]

OK we need things on this end now dont we