General information
Category:
Databases,Tables, Views, Indexing and SQL syntax
>We are running VFP6 on a WIN2K network. Our data resides on a network drive, and we have multiple users running the app that accesses the data from WIN2K and WIN98 workstations. We have a problem with SQL selects not always pulling the most recent updates. My understanding has always been that SQL gets data from disk, even if the table is open and buffered in the same work session. Yet I can bring up different results on 2 different work stations - one showing the newest added records and one missing them - after the data has definitely been saved and written to disk (I have timestamps in the records that support this). The SQL statement in question is:
>
> select loadno,orno,batch,floor from loadfile;
> where empty(mbol) and shipstatus='N';
> into cursor temp
>
>where loadfile is an alias name for an open table (loadin or loadout). I open this table at the beginning of the method and close it at the end, because each time the select is run, it could be on a different base table. Please let me know if you have any suggestions.
>Thanks in advance for your help!
>Deri
Hi Deri,
For performance reason, VFP keeps internal cache for a table. If command asks for data which can be found in the cache, VFP doesn't read from disk. SET REFRESH command controls how often the internal cache is discarded. Also, SYS(1104) should discard cache for all opened tables.
Thanks,
Aleksey.
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