>>An existiong appication has a form in which the "set the filter" property in the Data Enviroment to
>>

=(csoitecode = gcsitecode)

>>where csitecode is a field in the table and gcsitecode is a global variable. I used this format because it seems to work.
>>
>>In the valid method of a field it uses the seek function after using the file to as a different name to check if a value has already been entered for a site. Unless I add an explicti set filter" command for the aliased table it finds if a value is entered for other sites.
>>
>>Can some one please explain why?
>
>It sounds like you are using the table twice. The filter will not work across areas
Thanks, I did not write it but appears you are correct. I will go with adding the "set filter" command to the existing code.