Plateforme Level Extreme
Abonnement
Profil corporatif
Produits & Services
Support
Légal
English
Locked records in SQL statement.
Message
 
 
À
14/02/2000 23:39:49
Information générale
Forum:
Visual FoxPro
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
Divers
Thread ID:
00331985
Message ID:
00332226
Vues:
17
Hi Ed,
Thanks for the update on the ISRLOCKED() function. This has now become a totally useless function (IMO). Why even bother to take the time to find out if I have the record locked, why not just attempt to lock it with RLOCK()? If it returns .T. , then I have the record locked; if .F., I don't and what's more important is I can't.

As for the other items you mentioned, yes it can be taxing on a network and I know anytime you put a function into a SQL statement, the optimization factor goes out the window 99 out of 100 times. But with small tables (< 5000) and a half-way decent network, this is negligible (IMO).

If you really wanted to tax the network:
select *, !rlock() as locked from mytable into cursor c_temp
unlock in mytable
>A big problem here is that isrlocked() only reflects if the local system holds >a lock on the record in question, it does not tell you if the record is >eligible to be locked by the local system. And since the lock status can >change over time, the availability of a lock at the time of query may not be >the availability of a lock at a later time. The SELECT is a snapshot; it does >not dynamically change the status of records selected, especially where the >value of a function would have to be continuously updated against each record >of mytable, and this is inherently not Rushmore-optimizable. It's be very >expensive in terms of system overhead,netowrk traffic and server load if this >were not the case...
Larry Miller
MCSD
LWMiller3@verizon.net

Accumulate learning by study, understand what you learn by questioning. -- Mingjiao
Précédent
Suivant
Répondre
Fil
Voir

Click here to load this message in the networking platform