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.NET SqlConnection and SqlCommand
原标题:

I use SqlConnection and SqlCommand classes in my project with Dapper ORM but I ve got a strange problem. When I use SqlCommand for inserting a row in a db table it always work correct and when I select updated data form tables everything is fine but after close the application changes I made isn t commited like data have been saved in some cache. For example I created a simple table with only two columns (UserId (PK), and UserName (Unique)) and even in that case changes aren t saved. I m using the following code for inserting a row:

using (SqlConnection c = new SqlConnection(Settings.Default.UsersConnectionString))
        {
            c.Open();


            using (SqlCommand d = new SqlCommand())
            {
                d.CommandText = "INSERT INTO Users (UserName) VALUES ( SomeName )";
                d.CommandType = System.Data.CommandType.Text;
                d.Connection = c;
                int t = d.ExecuteNonQuery();
            }


            c.Close();
        }
问题回答

You are most likely inside of a transaction that is not committed. Perhaps the Dapper ORM has started a transaction and you must tell it to commit all changes.

At a guess, the default for your server has been set such that implicit transactions have been turned on. What this means is that, if you execute a command and no transaction is currently open, SQL Server will automatically start a transaction (as always). But when the command completes successfully, this transaction is left open, and needs an explicit commit to be issued.

To determine if this is the case, try querying @@OPTIONS:

IF @@OPTIONS & 2 > 0 
RAISERROR ( Implicit transactions are turned on , 1, 1)

This code in dapper should be:

var name = "SomeName";
int t  = c.Execute("INSERT INTO Users (UserName) VALUES (@name)", new {name});

Dapper does no internal transaction management, it must be passed in using the optional transaction param.

My gut is telling me you are connecting to a different db to insert the data. Either that of Damiens implicit transaction stuff, which is easy to validate.

It may be the database is automatically creating a transaction that s not being committed, try creating your own transaction in the code and committing it manually and see if that works

using (SqlConnection c = new SqlConnection(Settings.Default.UsersConnectionString))
{
   c.Open();
   using (SqlTransaction t = c.BeginTransaction("InsertIntoUsers"))
   {
        using (SqlCommand d = new SqlCommand())
        {
            d.CommandText = "INSERT INTO Users (UserName) VALUES ( SomeName )";
            d.CommandType = System.Data.CommandType.Text;
            d.Connection = c;
            int t = d.ExecuteNonQuery();
        }
        t.Commit();
   }
}




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