I'm using Entity Framework 4.0. Now I need to restrict access to a table while I'm reading from it or writing to it. Probably that's about transaction isolation level.
How do I do that?
Update
here is what I have
using (var db = new MyDb()) { using (TransactionScope scope = new TransactionScope()) { var item = db.MyItems.Single(x => x.Id == 5); item.Price = 12; db.SaveChanges(); scope.Complete(); } }
However, when I put a breakpoint at any line inside using (TransactionScope scope
and when I'm stopping there and then I go to Sql Server Management Studio and doing a select query (or even update!) from a table that is using inside a transaction, I'm not getting an error for some reason. But why? It must not allow me to read a data while a transaction is executing.
Entity Framework internally maintains transactions when the SaveChanges() method is called. It means the Entity Framework maintains a transaction for the multiple entity insert, update and delete in a single SaveChanges() method.
Accepted Answer. By default, a Transaction has an IsolationLevel of Serializable. Serializable is the highest level. It requires that the transaction completes before any other transaction is allowed to operate on the data.
One of the biggest reasons not to use Entity Framework Core is that your application needs the fastest possible data access. Some applications do a lot of heavy data operations with very high-performance demands, but usually business applications don't have that high of a performance demand.
Also, we can use SQL View with an NOLOCK keyword in a query to prevent deadlock. To overcome this issue we have to implement the single solution of the whole project, which READ UNCOMMITTED data to display on a website. Entity framework uses SQL server transaction ISOLATION LEVEL by default which READ COMMITTED data.
By default, a Transaction has an IsolationLevel of Serializable. Serializable is the highest level. It requires that the transaction completes before any other transaction is allowed to operate on the data.
It has the following restrictions:
This is a great blog post that explains how to use Transactions with the Entity Framework: Entity Framework transaction scope examples
In Entity Framework 6 the default IsolationLevel is changed to READ_COMMITTED_SNAPSHOT for databases created using Code First, potentially allowing for more scalability and fewer deadlocks. See the future spec of EF 6
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