Transaction support
In the previous section we learned that simultaneous changes by different users can be controlled by using a version column or the Concurrency Mode property. Sometimes the same user may have made several changes and some of the changes might not succeed. In this case we need a way to control the behavior of the overall update result. This is handled by transaction support.
LINQ to Entities uses the same transaction mechanism as ADO.NET, that is, it uses implicit or explicit transactions.
Implicit transactions
By default, LINQ to Entities uses an implicit transaction for each SaveChanges call. All updates between two SaveChanges calls are wrapped within one transaction.
For example, in the following code, we are trying to update two products. The second update will fail due to a constraint. However, as the first update is in a separate transaction, the update has been saved to the database and the first update will stay in the database:
static void TestImplicitTransaction...
