SQL Server temporal tables

[shivajiraot]

Does EF Core support code first approach for Temporal tables?
Looking to find a way to use Temporal tables with EF Core code first approach. Please guide me to the article if any existing already.
Thank you.

[rowanmiller]

For the most part, the fact that a table is temporal is opaque to the data layer - so from that point of view you should be fine to connect to an existing database with temporal tables.

Here are some limitations though, that we could address in EF:

• If you wanted to query a past state of the table you would need to use a raw SQL query.
• There is no way to make a table temporal in the model/migrations. So if you are using EF to create the database then you would need to hand edit the migration and use Sql(string) to make the table temporal.

[DavidBainbridgeRIT]

I second this as important. Temporal tables are fantastic. They cut out a lot of boiler plate but I need that information in the front end just as easily as in the back end.

[R00iBaard]

Agree, I would love to be able to set this up all via EF code first.

[reberinformatik]

👍 See also #2229

[lucasmaj]

I was absolutely bummed out to find out that currently there is no obvious way to query past state using lambda expressions. Is there any way to sneak in "AS OF <date_time>" into a query? (in EF6)

[divega]

@lucasmaj have you tried raw SQL queries as a workaround as explained above? E.g. in EF6 use SqlQuery() and FromSql() with EF Core. The latter is composable in LINQ.

[lucasmaj]

I haven't tried raw SQL. If EF6 had SqlQuery composable with LINQ it would do the trick for now. There is no way I would go with pure sql queries and abandon LINQ. Unless there could be a way for LINQ to pure sql back to entities in an automatic fashion.

Is there really no way to augment conversion of Expressions to SQL string so that some custom expression would translate to "AS OF" etc?

Thank you nonetheless.

I look forward to full support of Temporal Tables in an upcoming release. In the meantime, I am trying to make use of the SysStartTime/SysEndTime columns added to the table in the model (using CodeFirst), and I find that EF is trying to write to those columns even when I have the model property annotated with DatabaseGenerated(DatabaseGeneratedOption.Computed). Is there a way to get around this issue so that I can at least use those columns added for versioning without writing SQL?

[R00iBaard]

Any update on this? It would be very nice to have this 👍

[ajcvickers]

@R00iBaard This issue is in the Backlog milestone. This means that it is not going to happen for the 2.0 release. We will re-assess the backlog following the 2.0 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.