inspectdb should inform about composite keys.

[Damien]

Since django does not support multiple multiple-column primary keys, there should be a warning that the inspectdb result does not match exactly the database

​PR

[Mariusz Felisiak]

inspectdb is meant as a shortcut, not as definitive model generation. I would rather add a comment to the field's notes like we do in other cases. Raising a warning can be really annoying when you try to inspect a legacy database.

[Damien]

Updated the PR to change the warning to be a comment instead of printing it to stderr

[Anvesh Mishra]

I actually found a solution to this in SQLite3 through PRAGMA keyword but since PRAGMA is a SQLite3 specific command so my PR didn't passed the Jenkins tests ​https://github.com/django/django/pull/15683. If you could provide any suggestions cause if we use any of the introspection methods it only takes the first column as primary key and gives no info if there were other primary-key columns. Also I tried the changes given in PR ​https://github.com/django/django/pull/13736 but they didn't work.

[Anvesh Mishra]

Submitted a new PR with all the required changes. ​https://github.com/django/django/pull/15730

[Mariusz Felisiak <felisiak.mariusz@…>]

In 295249c:

Fixed #32234 -- Made inspectdb inform about composite primary keys.

[GitHub <noreply@…>]

In 9a3b7e5e:

Refs #32234 -- Removed hardcoded IntegerField in inspectdb test.

[nessita <124304+nessita@…>]

In 4c758581:

Refs #36052, #32234 -- Removed create_test_table_with_composite_primary_key flag in favor of using CompositePrimaryKey.

Now that Django properly supports creating models with composite primary
keys, the tests should use a CompositePrimaryKey field instead of a
feature flag to inline backend specific SQL for creating a composite PK.

Specifcially, the inspectdb's test_composite_primary_key was adjusted to
use schema editor instead of per-backend raw SQL.

[Natalia <124304+nessita@…>]

In 5d03c71b:

[5.2.x] Refs #36052, #32234 -- Removed create_test_table_with_composite_primary_key flag in favor of using CompositePrimaryKey.

Now that Django properly supports creating models with composite primary
keys, the tests should use a CompositePrimaryKey field instead of a
feature flag to inline backend specific SQL for creating a composite PK.

Specifcially, the inspectdb's test_composite_primary_key was adjusted to
use schema editor instead of per-backend raw SQL.

Backport of 4c75858135589f3a00e32eb4d476074536371a32 from main.

[GitHub <noreply@…>]

In dd133054:

Refs #36052, #32234 -- Fixed inspectdb tests for CompositePrimaryKey on Oracle.

Tests regression in 4c75858135589f3a00e32eb4d476074536371a32.

[Mariusz Felisiak <felisiak.mariusz@…>]

In 44bda7a6:

[5.2.x] Refs #36052, #32234 -- Fixed inspectdb tests for CompositePrimaryKey on Oracle.

Tests regression in 4c75858135589f3a00e32eb4d476074536371a32.
Backport of dd133054cb98f77577c06d7ef1f2391a865784bc from main