Entity Framework - Transaction

In all versions of Entity Framework, whenever you execute SaveChanges() to insert, update or delete the database, the framework will wrap that operation in a transaction. When you invoke SaveChanges, the context automatically starts a transaction and commits or rolls it back depending on whether the persistence succeeded.

This is all transparent to you, and you’ll never need to deal with it.

This transaction lasts only long enough to execute the operation and then completes.

When you execute another such operation, a new transaction starts.

Entity Framework 6 provides the following −

Database.BeginTransaction()

It is a simple and easier method within an existing DbContext to start and complete transactions for users.

It allows several operations to be combined within the same transaction and hence either all are committed or all are rolled back as one.

It also allows the user to more easily specify the isolation level for the transaction.

Database.UseTransaction()

It allows the DbContext to use a transaction, which was started outside of the Entity Framework.

Let’s take a look into the following example where multiple operations are performed in a single transaction. The code is as −

class Program {

   static void Main(string[] args) {

      using (var context = new UniContextEntities()) {

         using (var dbContextTransaction = context.Database.BeginTransaction()) {

            try {

               Student student = new Student() {
                  ID = 200, 
                  FirstMidName = "Ap", 
                  LastName = "Khan", 
                  EnrollmentDate = DateTime.Parse("2015-12-1")
               };

               context.Students.Add(student);

               context.Database.ExecuteSqlCommand(@"UPDATE Course SET Title = 
                   Calculus " + "WHERE CourseID = 1045");

               var query = context.Courses.Where(c ⇒ c.CourseID == 1045);

               foreach (var item in query) {
                  Console.WriteLine(item.CourseID.ToString()
                     + " " + item.Title + " " + item.Credits);
               }

               context.SaveChanges();
               var query1 = context.Students.Where(s ⇒ s.ID == 200);

               foreach (var item in query1) {
                  Console.WriteLine(item.ID.ToString() 
                     + " " + item.FirstMidName + " " + item.LastName);
               }

               dbContextTransaction.Commit();
            } catch (Exception) {
               dbContextTransaction.Rollback();
            }

         }
      }
   }
}

Beginning a transaction requires that the underlying store connection is open.

So calpng Database.BeginTransaction() will open the connection, if it is not already opened.

If DbContextTransaction opened the connection then it will close it when Dispose() is called.