Dapper.NETTransactions

Syntax

  • conn.Execute(sql, transaction: tran); // specify the parameter by name
  • conn.Execute(sql, parameters, tran);
  • conn.Query(sql, transaction: tran);
  • conn.Query(sql, parameters, tran);
  • await conn.ExecuteAsync(sql, transaction: tran); // Async
  • await conn.ExecuteAsync(sql, parameters, tran);
  • await conn.QueryAsync(sql, transaction: tran);
  • await conn.QueryAsync(sql, parameters, tran);

Using a Transaction

This example uses SqlConnection, but any IDbConnection is supported.

Also any IDbTransaction is supported from the related IDbConnection.

public void UpdateWidgetQuantity(int widgetId, int quantity)
{
    using(var conn = new SqlConnection("{connection string}")) {
        conn.Open();

        // create the transaction
        // You could use `var` instead of `SqlTransaction`
        using(SqlTransaction tran = conn.BeginTransaction()) {
            try
            {
                var sql = "update Widget set Quantity = @quantity where WidgetId = @id";
                var parameters = new { id = widgetId, quantity };

                // pass the transaction along to the Query, Execute, or the related Async methods.
                conn.Execute(sql, parameters, tran);

                // if it was successful, commit the transaction
                tran.Commit();
            }
            catch(Exception ex)
            {
                // roll the transaction back
                tran.Rollback();

                // handle the error however you need to.
                throw;
            }
        }
    }   
}

Speed up inserts

Wrapping a group of inserts in a transaction will speed them up according to this StackOverflow Question/Answer.

You can use this technique, or you can use Bulk Copy to speed up a series of related operations to perform.

// Widget has WidgetId, Name, and Quantity properties
public void InsertWidgets(IEnumerable<Widget> widgets)
{
    using(var conn = new SqlConnection("{connection string}")) {
        conn.Open();

        using(var tran = conn.BeginTransaction()) {
            try
            {
                var sql = "insert Widget (WidgetId,Name,Quantity) Values(@WidgetId, @Name, @Quantity)";
                conn.Execute(sql, widgets, tran);
                tran.Commit();
            }
            catch(Exception ex)
            {
                tran.Rollback();
                // handle the error however you need to.
                throw;
            }
        }
    }   
}