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 get_constraint method to fetch the primary key 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