>>I've been using sys(2015) as the field default for certain unique keys. Am I asking for trouble? I'm not sure how sys(2015) generates the string and for how long I can expect to keep getting unique strings..
>>Any other ideas for unique keys?
>
>Yes, some people are using that technique.
>
>However, the more used one is by using a data dictionary table that hold the actual key of each table and some others used fields. By having that table, you can also apply a locking mecanism which will garantee to always have a unique key.

We did some experimentation with sys(2015), when trying to decide the same question. This was under fpw 2.6. We found that 2 users can generate the same sys(2015) key within the same 1/100 th of a second.
Also sys(2015) is time/date based, so if your master clock is reset backwards, sys(2015) will generate duplicates. Based on this info, we decided this was not a good primary key or unique indicator. This is probably still true of VFP.

HTH
Glenn