Child Parent Transactions roll back

Question

I have a scenario in which I have to process multiple .sQL files, every file contains 3-4 insert or Update queries, now when any query in a file fails I do ro

Answer 1

Keep all insert, update queries in a try{..}catch(..){..} and if any exception occurs, in the catch roll the db transaction back.

     private void InsertFoo(SqlTransaction txn, string fooName)
     {
         using (var cmd = txn.Connection.CreateCommand())
         {
             try
             {
                 do your process here...
                 cmd.Commit();
             }
             catch(Exception ex)
             {
                cmd.Rollback();
             }
         }
     }

Answer 2

It seems you are looking for SavePoints, i.e. the option to partially roll back and then resume a larger transaction. AFAIK TransactionScope doesn't support SavePoints so you'll need to deal directly with the native provider (e.g. SqlClient if your RDBMS is Sql Server). (i.e. you cannot leverage the ability of TransactionScope to implement DTC equivalent of SavePoints, e.g. across distributed databases, disparate RDBMS, or parallel transactions)

That said, I would suggest a strategy where the user elects to skip or abort up front, before transactional processing begins, as it will be expensive awaiting UI response while a large number of rows are still locked - this will likely cause contention issues.

Edit

Here's a small sample of using SavePoints. Foo1 and Foo3 are inserted, Foo2 is rolled back to the preceding save point.

using (var conn = new SqlConnection(ConfigurationManager.ConnectionStrings["Foo"].ConnectionString))
{
    conn.Open();
    using (var txn = conn.BeginTransaction("Outer"))
    {
        txn.Save("BeforeFoo1");
        InsertFoo(txn, "Foo1");

        txn.Save("BeforeFoo2");
        InsertFoo(txn, "Foo2");
        txn.Rollback("BeforeFoo2");

        txn.Save("BeforeFoo3");
        InsertFoo(txn, "Foo3");
        txn.Commit();
    }
}

Where InsertFoo is:

private void InsertFoo(SqlTransaction txn, string fooName)
{
    using (var cmd = txn.Connection.CreateCommand())
    {
        cmd.Transaction = txn;
        cmd.CommandType = CommandType.Text;
        cmd.CommandText = "INSERT INTO FOO(Name) VALUES(@Name)";
        cmd.Parameters.Add(new SqlParameter("@Name", SqlDbType.VarChar)).Value = fooName;
        cmd.ExecuteNonQuery();
    }
}

And the underlying table is:

create table Foo
(
    FooId INT IDENTITY(1,1) NOT NULL PRIMARY KEY,
    Name NVARCHAR(50)
)