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fsprojects / SQLProvider

A general F# SQL database erasing type provider, supporting LINQ queries, schema exploration, individuals, CRUD operations and much more besides.
https://fsprojects.github.io/SQLProvider
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Any Optimistic Concurrency Control support (MS SQL Server)? #619

Open DunetsNM opened 5 years ago

DunetsNM commented 5 years ago

Description

I'm looking for a way to add Optimistic Concurrency Control in SQLProvider, based on TIMESTAMP columns (MSSQL). Similar to how it is done in Entity Framework.

Is there anything built-in? If not then a workaround or an extension?

Repro steps

  1. Create context, read a record from a table with TIMESTAMP column.

  2. Update some property of the record.

  3. Hit the breakpoint to make debugger stop just before ctx.SubmitUpdates(). Run the code in debugger.

  4. Concurrently update the record in MS SQL server (e.g. via SQL Management Studio) so record read in Step 1 becomes obsolete

  5. Resume debugger and execute ctx.SubmitUpdates()

Expected behavior

A runtime error saying that record was updated concurrently, no changes in database.

Actual behavior

SubmitUpdates() writes changes to database, regardless whether timestamp is obsolete or not.

Known workarounds

Don't know any out of the box. A stored procedure can be written instead which is tedious.

Related information

Thorium commented 5 years ago

There were something like this https://github.com/fsprojects/SQLProvider/pull/548

DunetsNM commented 5 years ago

This could be achieved with one UPDATE query, if timestamp column added to "WHERE" clause / throw exception if @@ROWCOUNT = 0 after the update

My intuition was that recordToUpdate.OnConflict <- OnConflict.Throw will do the trick but I was wrong.