Mike Yearwood
Toronto, Ontario, Canada
Walter Meester
HoogkarspelPays-Bas
Information générale
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
Hi Walter
>>Example: A 1 million record table contains 1% deleted records, and you want to recycle records. How you're going to solve this?
Some will add a DELETED() tag to be able to search for deleted() records. However with such tables performance degrades dramatic when using such table over a network (unless rushmore is set of with SET OPTIMIZE OFF).
It's best to add an INDEX ON .T. TAG delRec FOR DELETED() and search them with SEEK(.T.,"MyTable","DelRec"). Best story of all: The index is small because it only contains nodes for deleted records, optimizing performance.
<<
That's very elegant. Too bad I can't give you points for that one. However, if you think back to my comments to Jim Nelson about the datetime stamp, it would be best to recycle the earliest records first. Further, using a view, one would have to extract a deleted record to overwrite it with new data.
Its unfortunate VFP cannot optimize using filtered tags. I'll create a new thread posing this question.
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