>I have a table with code an description
>In the form I use a textbox to get these values. For the code I use an input mask of 99999.
>I check for the code so that it does not repeat when adding a new item. Also I check that both code and description are added.
>The problem is when I add an item, the default value for the code is zero, although no value is displayed. If I check for this value for not null it returns false (because it has a zero). If I add a description and save it, it saves the description and .null. for the code. If in the list I have another item with a zero code, the routine will tell that the code already exists.
>
>How can I achieve what I want? It seems simple, but I been messing too much around with it without getting a result.
>
>Thanks

Are you using the controlsource property of the textbox? I would suggest you to initialize the code textbox to zero. Assign zero to Value property of the textbox. And when validating the code it should be:

IF This.Value > 0
code here...
ENDIF