Question

I want to know what’s the difference between:

 DBCmd.Parameters.Add("user_name", IfxType.VarChar);
 DBCmd.Parameters["user_name"].Value = p_u; 

and

DBCmd.Parameters.Add("user_name", p_u);

What’s the best practice here, which one is safer, and does one perform better than the other?

Answer 1

In the example shown, the primary difference is that it knows the type to use is explicitly IfxType.VarChar – this might be important, depending on the exact situation, and whether IFX defaults strings as Char, VarChar, or LongVarChar. I honestly don’t know which of those it would select by default.

Being explicit is usually a good idea, but there is no need to re-fetch via the indexer, since the new parameter is returned from Add; I would probably suggest:

DBCmd.Parameters.Add("user_name", IfxType.VarChar).Value = p_u;

or maybe:

DBCmd.Parameters.Add("user_name", IfxType.VarChar, 20).Value = p_u;

where 20 is the size of the parameter.