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Shorter than sys(2015)
Message
De
04/02/2015 13:25:57
 
Information générale
Forum:
Visual FoxPro
Catégorie:
Codage, syntaxe et commandes
Versions des environnements
Visual FoxPro:
VFP 9 SP1
OS:
Windows XP SP2
Network:
Windows 2008 Server
Database:
Visual FoxPro
Application:
Web
Divers
Thread ID:
01614860
Message ID:
01614886
Vues:
74
>>SYS(2015) is not very good uniqe (for example for temp files on a multiuser scenario its not fast enough, I had crashes for non unique filles)
>>
>>This is by the way it is created.
>>
>>Lutz
>
>Are you sure you are not confused with sys(3)? I never had a problem with uniqueness of sys(2015), I just did a crude test creating a million records in a cursor, it took 0.786 seconds (1272 records every millisecond) and got zero collision.
>
>
>CREATE CURSOR c_test (PK I AUTOINC, VALUE C(10))
>
>lnStart			= SECONDS()
>FOR i = 1 TO 1000000
>	INSERT INTO c_test (value) VALUES (SYS(2015))
>NEXT i
>
>? SECONDS() - lnStart
>
>SELECT value, COUNT(*) cnt GROUP BY 1 ORDER BY 2 DESC FROM c_test HAVING cnt > 1
>
All my tests show SYS(2015) is unique in a given VFP session, but I don't believe it's unique across machines, and probably not across separate sessions on a single machine (though I've never tested that).

Tamar
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