DatabaseFeature supports_check_constraints and schema test_check_constraints

[Maximiliano Robaina]

DB Backends can define a database feature called supports_check_constraints, but what does it mean?

Running the schema tests, test_check_constraints skips it if the backend doesn't supports check constraints, but it seem like is trying to test column based check constraints. In my case Firebird just support table based check constraints, so the test_check_constraints fails.

My proposal is to change the supports_check_constraints name to something more explicit like supports_column_based_check_constraints.

[Tim Graham]

It was added in [ca9c3cd3] by Andrew. CCing him for his thoughts.

[Andrew Godwin]

Yes, it is only for column-based check constraints (the only type Django uses) - it's for things like PositiveIntegerField's check that >= 0 and stuff like that.

I'm fine with renaming it.

[Tim Graham]

In 82c935d44cac6f041628fff4f32d1efdde96e720:

Renamed DatabaseFeature.supports_check_constraints to supports_column_check_

Thanks maxi for the suggestion.

[Tim Graham]

In dc7d0f50e22bc52bc4656879452c482394347b75:

[1.7.x] Renamed DatabaseFeature.supports_check_constraints to supports_colum

Thanks maxi for the suggestion.

Backport of 82c935d44c from master