A C parser for CREATE and ALTER table SQLite statements

Re:A C parser for CREATE and ALTER table SQLite statements by masklinn on Tuesday August 15, 2023 @08:53AM (#37133364)

You can't drop a column which is still in use, I fail to see the issue with that.

I might see lamenting the lack of CASCADE but I've come to be less than fond of that in postgres, I don't consider that a feature.

And since mysql does not have DROP COLUMN ... CASCADE does it just... destroy any dependent when you try to drop a column being depended on? That sounds like the opposite of a feature.

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Re:A C parser for CREATE and ALTER table SQLite statements by evanelias on Tuesday August 15, 2023 @10:19AM (#37134325)

No, that's not how it works. If the column is used in a foreign key constraint, MySQL will prevent you from dropping the column. In that case, the ALTER statement will immediately fail with an error and take no action.

Otherwise, assuming there's no FK and it proceeds:

If the dropped column is used in any indexes, the index definitions are adjusted to no longer be keyed on that column. And if there's a single-column index on that dropped column, the index is also dropped. It's pretty much what you would always want to happen, without forcing you to needlessly indicate how the indexes need to be adjusted.

It doesn't automatically adjust any views, triggers, procs, funcs, etc that reference the column though.

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