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Rushmore Design Flaw Heads-UP!
Message
From
08/07/1999 13:26:37
 
General information
Forum:
Visual FoxPro
Category:
Databases,Tables, Views, Indexing and SQL syntax
Miscellaneous
Thread ID:
00238826
Message ID:
00238969
Views:
23
>If you have a large table, and perform a SQL Select, Rushmore might USE AGAIN the table with a filter in effect. The BIG problem with this (which I think is a bug), is that the entire file is still available as are the records of original files. Rushmore should always return the same type of cursor regardless of what it had to do. The bug is also in the GO command, which disregards the rushmore filtered file and actually GO's to the record in the parent file, not the query result!
>
>For example:
>
>SELECT * FROM TESTFILE WHERE KEYFIELD = 1 && Keyfield is indexed
>* Should return 1 record
>GO 1
>? KEYFIELD
>GO 2
>? KEYFIELD && prints record 2 keyfield
>GO 3
>? KEYFIELD && prints record 3 keyfield
>
>Same Code with NOFILTER:
>SELECT * FROM TESTFILE WHERE KEYFIELD = 1 NOFILTER
>GO 1
>? KEYFIELD
>GO 2 && EOF error
>GO 3 && EOF error

This is by design, and only happens when you do this type of SELECT (ie. one table, with no calculated fields, etc.). There are ways to get around it. Look at the NOFILTER clause. You can also add a calculated field. Note that when you do a multi-table join, VFP does a USE AGAIN on the tables.
Craig Berntson
MCSD, Microsoft .Net MVP, Grape City Community Influencer
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