Re: OK to delete records while finding them?
This WebDNA talk-list message is from 2000
It keeps the original formatting.
numero = 32479
interpreted = N
texte = >Is there some inherent danger in deleting a record from a db within >a [founditems] loop which is finding >records in that same db?Yes, this is bad. When you do a [SEARCH], webcat creates an internal list of record numbers. It then uses that list to call up the info from the correct lines. If you do a [DELETE], the internal list stays the same, but the info that's really in the database is wrong.For example, let's say your search returns the first, second, and third records in a database:Sku 1 2 3After the first [DELETE], your db might look like thisSKU 2 3So on the next iteration, webcat will look at the second line. Instead of finding the record with SKU=2, it will find the record with SKU=3. Since it doesn't know you don't want that, bad things happen.A simple solution is to replace a field with a unique phrase/word and then delete all those records after the [FOUNDITEMS] loop is complete (this will preserve the line numbering):[SEARCH db=some.db&neSKUdatarq=[SKU]] [FOUNDITEMS] [REPLACE db=some.db&eqSKUdatarq=[SKU]]SKU=DELETEME[/REpLACE] [/FOUNDITEMS] [/SEARCH] [DELETE db=some.dn&eqSKUdatarq=DELETEME]Michael------------------------------------------------------------- This message is sent to you because you are subscribed to the mailing list
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Associated Messages, from the most recent to the oldest:
>Is there some inherent danger in deleting a record from a db within >a [founditems] loop which is finding >records in that same db?Yes, this is bad. When you do a [search], webcat creates an internal list of record numbers. It then uses that list to call up the info from the correct lines. If you do a [delete], the internal list stays the same, but the info that's really in the database is wrong.For example, let's say your search returns the first, second, and third records in a database:Sku 1 2 3After the first [delete], your db might look like thisSKU 2 3So on the next iteration, webcat will look at the second line. Instead of finding the record with SKU=2, it will find the record with SKU=3. Since it doesn't know you don't want that, bad things happen.A simple solution is to replace a field with a unique phrase/word and then delete all those records after the [founditems] loop is complete (this will preserve the line numbering):[SEARCH db=some.db&neSKUdatarq=[SKU]] [founditems] [REPLACE db=some.db&eqSKUdatarq=[SKU]]SKU=DELETEME[/REpLACE] [/FOUNDITEMS] [/SEARCH] [DELETE db=some.dn&eqSKUdatarq=DELETEME]Michael------------------------------------------------------------- This message is sent to you because you are subscribed to the mailing list . To unsubscribe, E-mail to: To switch to the DIGEST mode, E-mail to Web Archive of this list is at: http://search.smithmicro.com/
Michael Winston
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