如何在 Asp.Net 中使用 Web Api 在 Entity Framework 6 中实现事务？

Question

Is there any way to implement a transaction in Entity Framework 6 with Web API in Asp.Net?

I am inserting 10 tables separately using Web API calls in a single asp.net web form. I am seeking ideas or technical feasibility suggestions using Entity framework and Web API.

Answer 1

Keep in mind:

In Entity Framework, the SaveChanges() method internally creates a transaction and wraps all INSERT, UPDATE and DELETE operations under it. Multiple SaveChanges() calls, create separate transactions, perform CRUD operations and then commit each transaction.

If you really want to perform transaction its really easy:

using (var context = new SomeDbContext())
{
 using (DbContextTransaction transaction = context.Database.BeginTransaction()) {
   //do stuff
   context.SaveChanges();
   // multiple saves
   context.SaveChanges();
   transaction.Commit(); // this is one transaction
 }
}

Answer 2

Below is the sample code snippet would give a clarity on the multiple tables Create or Update transaction. The first table column ID is the foreign key for other child tables. So if there is an exception on child table insertion, the parent table record will also get rolled back. And thus the whole table which is included in transaction will get rolled back successfully.

    public bool CreateOrUpdateEmployee(Common common)
    {
        bool IstransactionComplete= false;
        EmployeeEntities DbContext = new EmployeeEntities();

        using (var transaction = DbContext.Database.BeginTransaction())
        {
            try
            {
                if (common.Mode == Modes.CREATE) //Modes - User defined Enum
                {
                    DbContext = CreateFinanceEmployees(common, DbContext); //DbContext.savechanges() inside this method.

                    DbContext = CreateManufacturingEmployee(common, DbContext); //DbContext.savechanges() inside this method.

                    DbContext = CreateLogisticsEmployee(common, DbContext);  //DbContext.savechanges() inside this method.
                }
                else
                {
                    DbContext = UpdateFinanceEmployees(common, DbContext);  //DbContext.savechanges() inside this method.

                    DbContext = UpdateManufacturingEmployee(common, DbContext);  //DbContext.savechanges() inside this method.

                    DbContext = UpdateLogisticsEmployee(common, DbContext);  //DbContext.savechanges() inside this method.
                }

                **transaction.Commit();**

                IstransactionComplete=true;
            }
            catch (Exception ex)
            {
                **transaction.Rollback();**

                IstransactionComplete=false;
            }
            finally
            {
                transaction.Dispose();
            }
        }
        return IstransactionComplete;
    }

Answer 3

Yes.

You can use the context provided by EF to create a transaction scope. At the end of the scope you can commit or rollback.

You can do something like that:

class WebController
{
    public Response restMethod()
    {
        var context = getYourDBCOntext();
        using(var dbContextTransaction = context.Database.BeginTransaction())
        {
            try {
                // do something with the DB
                context.Database.ExecuteSqlCommand( /* sql command */ );

                // save changes
                context.SaveChanges();
                // commit transaction
                dbContextTransaction.Commit();
            catch(Exception)
            {
                // Rollback in case of an error
                dbContextTransaction.Rollback();
            }
        }
    }
}