What's the most DRY-appropriate way to execute an SQL command?

Posted by Sean U on Stack Overflow See other posts from Stack Overflow or by Sean U
Published on 2012-09-24T21:16:34Z Indexed on 2012/09/24 21:37 UTC
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I'm looking to figure out the best way to execute a database query using the least amount of boilerplate code. The method suggested in the SqlCommand documentation:

private static void ReadOrderData(string connectionString)
{
    string queryString = "SELECT OrderID, CustomerID FROM dbo.Orders;";
    using (SqlConnection connection = new SqlConnection(connectionString))
    {
        SqlCommand command = new SqlCommand(queryString, connection);
        connection.Open();
        SqlDataReader reader = command.ExecuteReader();
        try
        {
            while (reader.Read())
            {
                Console.WriteLine(String.Format("{0}, {1}",     reader[0], reader[1]));
            }
        }
        finally
        {
            reader.Close();
        }
    }
}

mostly consists of code that would have to be repeated in every method that interacts with the database.

I'm already in the habit of factoring out the establishment of a connection, which would yield code more like the following. (I'm also modifying it so that it returns data, in order to make the example a bit less trivial.)

private SQLConnection CreateConnection()
{
    var connection = new SqlConnection(_connectionString);
    connection.Open();
    return connection;
}

private List<int> ReadOrderData()
{
    using(var connection = CreateConnection())
    using(var command = connection.CreateCommand())
    {
        command.CommandText = "SELECT OrderID FROM dbo.Orders;";

        using(var reader = command.ExecuteReader())
        {
            var results = new List<int>();
            while(reader.Read()) results.Add(reader.GetInt32(0));
            return results;
        }
    }
}

That's an improvement, but there's still enough boilerplate to nag at me. Can this be reduced further? In particular, I'd like to do something about the first two lines of the procedure. I don't feel like the method should be in charge of creating the SqlCommand. It's a tiny piece of repetition as it is in the example, but it seems to grow if transactions are being managed manually or timeouts are being altered or anything like that.

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