[RBASE-L] - RE: Deleting dups

[Doug Hamilton]

Read it?  I thought you wrote it!
D

Emmitt Dove wrote:

Got me there, Paul.  Guess I should read the doc more often!

 

Emmitt Dove

Manager, Converting Applications Development

Evergreen Packaging, Inc.

emmitt.d...@everpack.com

(203) 214-5683 m

(203) 643-8022 o

(203) 643-8086 f

emmitt.w.d...@comcast.net

 

From: rbase-l@rbase.com [mailto:rbase-l@rbase.com] On Behalf Of Paul InterlockInfo
Sent: Thursday, August 06, 2009 4:06 PM
To: RBASE-L Mailing List
Subject: [RBASE-L] - RE: Deleting dups

 

About the DELETE DUPLICATES Command

Use DELETE DUPLICATES to delete duplicate rows from a table. A duplicate row is a row where the values for each column are exactly the same as those in another row in the table. This command deletes all but the first row for each set of duplicate rows.

DELETE DUPLICATES processes faster when the table contains an indexed column and the USING collist option is used.

Rules for Column Deletion

 

 

And I thought line “DELETE DUPLICATES processes faster when the table contains an indexed column and the USING collist option is used.” Was right.

 

Sincerely,

Paul D.

 

 

 

 

 

From: rbase-l@rbase.com [mailto:rbase-l@rbase.com] On Behalf Of Emmitt Dove
Sent: Thursday, August 06, 2009 3:50 PM
To: RBASE-L Mailing List
Subject: [RBASE-L] - RE: Deleting dups

 

AFAIK, DELETE DUPLICATES will not use indexes.

 

Emmitt Dove

Manager, Converting Applications Development

Evergreen Packaging, Inc.

emmitt.d...@everpack.com

(203) 214-5683 m

(203) 643-8022 o

(203) 643-8086 f

emmitt.w.d...@comcast.net

 

From: rbase-l@rbase.com [mailto:rbase-l@rbase.com] On Behalf Of karentel...@cs.com
Sent: Thursday, August 06, 2009 3:05 PM
To: RBASE-L Mailing List
Subject: [RBASE-L] - Deleting dups

 

I'm sure I can test this but I'm lazy ...  I need to delete duplicates on a huge table using 2 of the columns.   Both of these columns are normally indexed.   I'm wondering if I should drop the indexes before I do the delete?   I would think that as it deletes the dups it has to update the indexes, which would take longer.  On the other hand, does the command actually use the index, thereby making the deletion faster?   If no one knows off the top of their head then I'll time both of the methods...

Karen