Json Columns initial work

[maumar]

trafficstars

Finished work:

• basic metadata,
• property/navigation access translation,
• materialization (entity, collection, with nesting),
• honoring json property name attribute for custom naming
• validation,

Remaining work:

• migration,
• update,
• collections of primitives,
• array access/operations (force non-tracking!)
• some metadata fixes (e.g. using actual type mapping for properties mapped to json, rather than default mappings), flowing json type info (npgsql),
• custom serialization (???),
• lots of fixes, cleanups, documentation,
• testing (WIP)

blocked:

• json owned entity having navigation to non-owned entity
• json collection with ordinal key explicitly defined
• inheritance (apart from TPH)
• table splitting

[AndriySvyryd]

When you add validation also throw if an entity type is mapped to JSON, but the principal type is not mapped to a table or view (and add a note to support this for raw SQL and function mappings in #19970 and #21627)

[AndriySvyryd]

Add a test to RelationalModelTest that has nested JSON types and some of the column names are the same on between levels

[smitpatel]

Requires actual query tests.

Why don't we not allow projection member binding for JsonEntityExpression?

[smitpatel]

Are we planning to support navigations from inside the JSON document outside and vice versa? If so, I didn't think this would be part of a 1st version - it certainly hasn't been requested on the PG side (and sounds complicated).

It came up yesterday and we need to have a nice design meeting discussion about it

[smitpatel]

Add validation for not allowing JSON column for TPT/TPC

[ajcvickers]

👍

[smitpatel]

    private readonly IDictionary<ParameterExpression, IDictionary<IProperty, int>> _materializationContextBindings

can make these all dictionaries concrete Dictionary type?

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Refers to: src/EFCore.Relational/Query/RelationalShapedQueryCompilingExpressionVisitor.ShaperProcessingExpressionVisitor.cs:133 in b40e728. [](commit_id = b40e7283c5f6382b7b5d062fc75d0f8019043d37, deletion_comment = False)

[smitpatel]

    var isTph = entityType.FindDiscriminatorProperty() != null;

@AndriySvyryd can we just use mapping strategy method now?

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Refers to: src/EFCore.Relational/Metadata/Internal/RelationalModel.cs:364 in d0f43e3. [](commit_id = d0f43e38a4e320169e272647f08526532e9c8be9, deletion_comment = False)

[AndriySvyryd]

@AndriySvyryd can we just use mapping strategy method now?

Yes

[AndriySvyryd]

Is this draft ready for review yet? So we can really start commenting

[smitpatel]

                earlierClientProjectionCount = _clientProjections.Count;

This is where we do process after lifting from single result subquery. Recompute the dedupe map here from this point to end point.

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Refers to: src/EFCore.Relational/Query/SqlExpressions/SelectExpression.cs:846 in f2ab2b9. [](commit_id = f2ab2b9ba510d47ab49e39f8d4b325cfd19873ae, deletion_comment = False)

[smitpatel]

cc: @AndriySvyryd to review metadata/update pipeline changes.