Support mapping multiple types to the same JSON column (sharing)

[AndriySvyryd]

This would allow mapping different owned or complex types to a single JSON column as long as they are declared on sibling types in a TPH hierarchy.

Depends on #38060
Related: #38061

This doesn't cover cases where a discriminator value inside the JSON would be used. That would be covered by #27779 or #38059

[ajcvickers]

This is not easy, but would enable some interesting and useful scenarios--see #29456.

[codelovercc]

@ajcvickers Hi, I am so excited about this feature. Any news? Will this be supported in Entity Framework Core 8 (EF Core 8; EF8) ?

[ajcvickers]

This issue is in the Backlog milestone. This means that it is not planned for the next release (EF Core 8.0). We will re-assess the backlog following the this release and consider this item at that time. However, keep in mind that there are many other high priority features with which it will be competing for resources. Make sure to vote (👍) for this issue if it is important to you.

[joakimriedel]

Please keep on voting for this issue so it might get prioritized for v9! 👍

With TPH this would make for a very powerful storage of metadata for similar, yet different, entities. Now the database would get flooded with columns like MetadataJsonA, MetadataJsonB, MetadataJsonC for each entity in the hierarchy. Once this gets implemented however, I imagine it will be easy to consolidate all columns to a single MetadataJson column.