Primitive collections

[roji]

This user story tracks support for primitive collections, i.e. the ability to map a property of type int[] to the database, as a JSON array (by default). Where supported, such collections are also fully queryable via the regular LINQ operators.

As a by-product of this, the translation for intParam.Contains(b => b.Property) would be changed from the current IN with constants translation to a string parameter containing an JSON array, which would be unpacked at the database and queried via the standard means. This resolves #13617, which is a long-standing, highly-voted performance issue.

Done in 8.0

• [x] #29427
  • Note that in PostgreSQL, native database arrays will be used instead.
• [x] #30426
• [x] #13617
• [x] #30724
• [x] #30677
• [x] #30727
• [x] #30730
• [x] #28688
• [x] #30732
• [x] #31489
• [x] #31030
• [x] #30919
• [x] #30922
• [x] #30921
• [x] #30734

Done in 9.0

• [x] #25364
• [x] #25765
  • [x] #25700
  • [x] #25701
  • [x] #16926
• [x] #4179
• [x] #25364

Backlog

• [ ] #30630
• [ ] #31109
• [ ] #31069
• [ ] #30712
  • [ ] #30711
• [ ] #30713
• [ ] #25163
• [ ] #30786
• [ ] #31287
• [ ] #29825

Related issues

• [ ] #26824
• [ ] #25343

[vchirikov]

@roji I'm sorry to bother you, I found that builder.OwnsMany(x => x.ListOfStructsProperty, x => x.ToJson()); doesn't work on net8.0 and I didn't find the issue to track. Should I create it or the issue is already here somewhere?

[roji]

@AndriySvyryd do we have an issue already tracking this? I found #28861 but that seems to be something else (am still not sure exactly what though 😅 )

In any case, we're likely to work on mapping JSON through complex types (as opposed to owned entities), and should make that work there - JSON mapping via owned entity types is likely to be de-prioritized.

[AndriySvyryd]

@vchirikov ~Mapping owned collections to JSON is generally supported. Can you open a new issue that shows the types being mapped, the error that you get and how you expect the JSON to look?~

Oh, I see now. We only allow structs to be mapped as complex types. So as @roji mentioned, be on the lookout for #31252 and #31411

[zN3utr4l]

Do you have any suggestions for implementing a List<List< int>>? since it doesn't work with OwnsMany either.

https://github.com/dotnet/efcore/issues/33913

[roji]

@zN3utr4l nested primitive collection support is tracked by #30713 - that's not currently supported.