Speaking of SQL. Take this sql query in a datadapter
SELECT Name, Street FROM Customer WHERE id = @idCust
The @ in front of idCust indicate idCust is a paramater. You can access these parameters from code. Being a bad or lazy typer (I'm both) it's tempting to do this by number.
sqlDataAdapter.SelectCommand.Parameters[0].Value = 12;
In maintanable code it should be done by name
sqlDataAdapter.SelectCommand.Parameters[“@idCust“].Value = 12;
The @ is part of the parameter's name. My first guess would have been different.
Peter