>>Hi Everybody,
>>
>>To generate a unique record id value, in lieu of using either:
>>
>>1. the AUTOINC field type
>>2. using a table that houses a LastNumber field and have a GetLastNumber() function to lock and return value.
>>
>>Will using SYS(2015) do the job? I mean, is its uniqueness 'guaranteed' if its being invoked by 100 or more workstations simultaneously?
>>
>>Thanks
>>Dennis
>
>Its uniqueness would even break with 2 workstations. Use a GUID.
>Cetin

True, since SYS(2015) is derived from the workstation clock, and workstations on networks are never completely synchronized. It is a pretty sure-fire unique value on one single system, though -- running SYS(2015) in a tight loop on my 3.4 Pentium with 2GB memory did not produce any duplicates during 1000 iterations, though. But a GUID would give you a truly unique ID, every time.

The LastPKID() -strategy has a few important benefits, however: While it is a bit more (setup) work than simply getting a GUI, with this approach you can create integer keys, which take a whole lot less space than GUI and are a whole lot faster to search (in a huge data table).

I don't personally completely trust the autoincrement -field property in VFP -- it has problems specifically if you use views or stored procedures. Also, since the current autoinc value is stored in the table header, it is at risk during crashes.

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By the wey, Cetin, how do you like Ideablade Devforce now that you've been using it for a while? I've been looking at it seriously lately (although I use Strataframe for a lot of my .NET work), mainly because of the Business Object Server (BOS) component, which will play very nicely with Microsoft's new Silverlight environment. As I understand it, Silverlight uses web services to get and set data, and Devforce's BOS can serve data as if it was a web service while making sure that no application specific business rules are broken -- IOW, business rules are created and maintained in one place, whether you have a "regular" n-tier app or one developed with Silverlight.

Any comments (good or bad), tips/tricks about the development system in general or major functions in specific?


Thanks!