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entity-frameworktransactions
beibichunai
beibichunai

Reputation: 138

EF consistency between two or more reads

In this page in Microsoft's documentation on EF it is stated literally

Entity Framework does not wrap queries in a transaction

If I am right, this means that sql reads are not implied with transactions and thus every select in our code is executed independently. But if this is so, can we ensure that two reads are consistent between each other? In the typical scenario, is there a warranty that the sum of the loaded amount of A and the loaded amount of B will be right (in some connection) if a transfer between A and B is started (in a different connection) between the read of A and the read of B? Would Entity Framework be able to solve this case in some way?

Upvotes: 1

Views: 288

Answers (1)

David Browne - Microsoft
David Browne - Microsoft

Reputation: 89091

The built-in solution in EF is client-side optimistic concurrency. On update EF will build a query that ensures that the row to be updated has not been changed since it was read.

Properties configured as concurrency tokens are used to implement optimistic concurrency control: whenever an update or delete operation is performed during SaveChanges, the value of the concurrency token on the database is compared against the original value read by EF Core.

If the values match, the operation can complete. If the values do not match, EF Core assumes that another user has performed a conflicting operation and aborts the current transaction.

You can also opt in to Transactions at whatever isolation level you choose, which may provide similar protections. Or use Raw SQL queries with lock hints for your target database.

Upvotes: 1

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