Improvements to relational database mappings

[ajcvickers]

This is a grouping of related issues. Feel free to vote (👍) for this issue to indicate that this is an area that you think we should spend time on, but consider also voting for individual issues for things you consider especially important.

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This an "epic" issue for the theme of improvements to relational mapping constructs. Specific pieces of work will be tracked by linked issues.

Done in 6.0

• [x] #8023

Done in 7.0

• [x] #3170
• [x] #19811
• [x] #620
• [x] #245
• [x] #4021
• [x] #3954
• [x] #28595

Done in 8.0

• [x] #365

Planned for 9.0

• [x] #11261

Backlog

• [ ] #10739
• [ ] #22060
• [ ] #27970
• [ ] #27971
• [ ] #27972
• [ ] #27973
• [ ] #27974
• [ ] #28204
• [ ] #2595
• [ ] #827
• [ ] #21569
• [ ] #19970
• [ ] #20339
• [ ] #885
• [ ] #10665
• [ ] #10140
• [ ] #21509
• [ ] #20931
• [ ] #12837
• [ ] #8624
• [ ] #11502
• [ ] #11001
• [ ] #4415
• [ ] #2611
• [ ] #6717
• [ ] #11336
• [ ] #10768
• [ ] #10862
• [ ] #27192
• [ ] #27975
• [ ] #28433
• [ ] #28434
• [ ] #28436
• [ ] #28438
• [ ] #28439
• [ ] #28511
• [ ] #28571
• [ ] #33676
• [ ] #10770
• [ ] #32028
• [ ] #28043
• [ ] #27828
• [ ] #27779
• [ ] #28441
• [ ] #28442
• [ ] #28574
• [ ] #28592
• [ ] #28443
• [ ] #28452
• [ ] #28584
• [ ] #28591
• [ ] #28593
• [ ] #28594