Hi Vlad,

I knew you would be the first, who would try to answer :)
Actually, my manager just came to my place and asked me, do I know an answer on this question (how to determine in which DS the particular alias (table) is opened). I thought a little and said: 'There is no way to find this info'.
Your message basically confirms this statement. Or, at least, there is no easy way to find it.

Now, let's consider this situation:
Say, we have a form with private DS and some tables opened. Table1, Table2, etc.
You're sitting in this private DS and check
?used('Table1')
return .t.

You switch to default DS and check used('Table1') What does it return?

Also, how can you find out, how many and their IDs DS do you have?
Mike Helland suggested one approach here (using On Error idea).

Thanks for your help.

>Hi!
>
>In VFP 6 there are no way to scan all data sessions to find alias. You will need to write special code in the load method of your form to register, and code in destroy method to unregister data sessions. Store them in the public array. Than you will know which data sessions opened and can easy scan all of them for required alias.
>
>Hope this helped.
>
>>Is there a way to find out in which DS (number) the particular table (alias) is opened? May be VFP function?
>>