Document breaking changes in the update pipeline

[roji]

Issues:

• Stop wrapping single changes in transactions where possible efcore#27439
• SQL Server: Optimize SQL Server OUTPUT clause usage when retrieving database-generated values  efcore#27372
• Allow managing transactions via SQL commands in the update pipeline efcore#27532
• Use RETURNING/OUTPUT clause for UPDATE/DELETE efcore#27547

Since the breaking changes here are quite wide-reaching, reach out proactively to provider writers to help them.

[ajcvickers]

@roji I didn't work on this when doing the 7.0 breaking changes because I'm not sure what needs doing where.

[roji]

Yeah, to be honest, I'm not sure what user-facing breaking changes we have here (apart from the trigger trouble which is already documented). The fact we no longer wrap single statements in a transaction may theoretically cause a behavior change in some scenarios, but I'd have to think hard to find such a scenario (we should maybe wait until a user hits one?).

(There are certainly many provider-facing breaking changes here, but I'm not a fan of doing a breaking change note for those)

[ajcvickers]

Agreed.

[ErikEJ]

Maybe that EF Core runs too fast now? 🤣

[roji]

@ErikEJ something like this...

[ErikEJ]

Exactly. Luckily you have a "go slow" switch.