[6.0.1] Return null schema for unmapped entity types.

[AndriySvyryd]

Fixes #26651

Description

We started including the default schema in each ToTable call in the model snapshot, even if it was to mark an entity type as not mapped - ToTable(null, "schema"), which doesn't work.

Customer impact

If the model has a default schema and unmapped entity types the model snapshot in the generated migration throws an exception when used.

How found

Customer reported on 6.0

Regression

Yes, this worked in 5.0

Testing

Added test for this scenario.

Risk

Low, the fix just affects models with unmapped entity types. Also added a quirk mode.

[marekott]

Hi @AndriySvyryd, I have a question regarding database views and their schema after this change.

efcore/src/EFCore.Relational/Extensions/RelationalEntityTypeExtensions.cs

Line 140 in b906ca3

if (entityType.GetTableName() == null)

If statement above will always return null if it is called on entity representing database view. For views there is a seperate method:

efcore/src/EFCore.Relational/Extensions/RelationalEntityTypeExtensions.cs

Line 287 in b906ca3

public static string? GetViewName(this IReadOnlyEntityType entityType)

Is it expected behaviour? With "Microsoft.EntityFrameworkCore.Relational" Version="6.0.0" checking schema name with

efcore/src/EFCore.Relational/Extensions/RelationalEntityTypeExtensions.cs

Line 138 in b906ca3

public static string? GetSchema(this IReadOnlyEntityType entityType)

for entity being database view would return correct schema, not null like now.

[AndriySvyryd]

@marekott That's the intended behavior. Use GetViewSchema() instead.

[marekott]

Ok, thanks