Sql – Can you include linq-to-sql changes and ADO.NET dataset table adapter updates in a single transaction

ado.netdatasetdevartlinq-to-sqltransactions

Here are the relevant technologies that I'm working with:

  • Devart's dot Connect for Oracle (to facilitate Linq-to-Sql for Oracle).
  • Strongly Typed ADO.NET Datasets.
  • An Oracle database.

Here's the challenge:

  • My legacy code submits database updates with ADO.NET datasets and table adapters.
  • I'd like to begin converting that code over to Linq-to-Sql, but I'd like to do it piecemeal to minimize code churn and risk.

Here's my proof of concept schema:

Parent Table

  • Parent.Id
  • Parent.Name

Child Table

  • Child.Id
  • Child.ParentId
  • Child.Name

Here's my proof of concept code block:

using System;
using System.Data.Common;
using DevArtTry1.DataSet1TableAdapters;

namespace DevArtTry1
{
    class Program
    {
        static void Main(string[] args)
        {
            using (DataContext1 dc = new DataContext1())
            {
                dc.Connection.Open();
                using (DbTransaction transaction = dc.Connection.BeginTransaction(System.Data.IsolationLevel.ReadCommitted))
                {
                    dc.Transaction = transaction;

                    Parent parent = new Parent();
                    parent.Id = 1;
                    parent.Name = "Parent 1";
                    dc.Parents.InsertOnSubmit(parent);
                    dc.SubmitChanges(); // By virtue of the Parent.Id -> Child.ParentId (M:N) foreign key, this statement will impose a write lock on the child table.

                    DataSet1.CHILDDataTable dt = new DataSet1.CHILDDataTable();
                    DataSet1.CHILDRow row = dt.NewCHILDRow();
                    row.ID = 1;
                    row.PARENTID = 1;
                    row.NAME = "Child 1";
                    dt.AddCHILDRow(row);

                    CHILDTableAdapter cta = new CHILDTableAdapter();
                     // cta.Transaction = transaction;  Not allowed because you can't convert source type 'System.Data.Common.DbTransaction to target type 'System.Data.OracleClient.OracleTransaction.
                    cta.Update(dt); // The thread will encounter a deadlock here, waiting for a write lock on the Child table.
                    transaction.Commit();
                }
            }

            Console.WriteLine("Successfully inserted parent and child rows.");
            Console.ReadLine();
        }
    }
}
  • As the comments above indicate, the thread will halt indefinitely on the child data adapter's update call because it will wait indefinitely for a write lock on the Child table. [Note the foreign key relationship: Parent.Id -> Child.ParentId (M:N)]

Here's my question:

  • I want to wrap the entire code block
    in a transaction.
  • Can I do this? Considering that:
    • I want to commit an update on the Parent table with
      Linq-to-Sql's SubmitChanges method…
    • And I want to commit an
      update on the Child table with an
      ADO.NET dataset table adapter.

Here are two interesting footnotes:

  1. This whole things works in
    reverse. That is, if I wanted to
    submit changes to the parent table
    with a data adapter and changes to
    the child table with linq-to-sql…
    that would work.

  2. I tried to explicitly attach the transaction to the dataadapter, but the compiler won't allow it because it is a different type of transaction.

                    CHILDTableAdapter cta = new CHILDTableAdapter();
            cta.Transaction = transaction; // Not allowed because you can't convert source type 'System.Data.Common.DbTransaction' to target type 'System.Data.OracleClient.OracleTransaction'.
            cta.Update(dt);
            transaction.Commit();

Best Answer

I don't know anything about Oracle's transactions... but on the dotnet side you should be fine to control the transaction yourself. Make sure both technologies are using the same connection instance.

When we control transactions through the connection instead of through the ORM, we use transaction scope: http://msdn.microsoft.com/en-us/library/ms172152.aspx

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