issues-229 add column if not exists

[ikrivosheev]

PR Info

• Closes support ifnotexist(column) add column #229

• Dependencies:
  • issues-213 Add support for multiple ALTER table #277

Adds

Add support for query like:

ALTER TABLE name
    ADD COLUMN IF NOT EXISTS column_name data_type

for PostgreSQL and for MySQL. For SQLLite this is ignored

[tyt2y3]

I don't think this works for MySQL, may be just MariaDB?

[tyt2y3]

I like the addition of this API. But a bool does not seem forword looking, we might want to create a new type AddColumnOption (or some reasonable name)?

[ikrivosheev]

Thank you for the review.

I don't think this works for MySQL, may be just MariaDB?

Yes, you are right! Fix

I like the addition of this API. But a bool does not seem forword looking, we might want to create a new type AddColumnOption (or some reasonable name)?

Done.

[ikrivosheev]

@tyt2y3 I have done. Can you review it please?)