Excluding NULL values in Btree index (OpenInsight 32-bit Specific)
At 31 JAN 2006 11:27:00PM Wilhelm Schmitt wrote:
How can I create a Btree index on a field, excluding NULL values ?
We have a large file, where one of the indexed fields contains lots of NULL values and there won't be any searches on NULL values.
The index rebuild should only contain the keys where FIELD # "". In our case it means that instead of 2.5 GB index size it should "only" be 100 MB.
Any ideas are welcome.
Regards
Wilhelm
At 01 FEB 2006 04:04AM [url=http://www.sprezzatura.com]The Sprezzatura Group[/url] wrote:
You might want to look at this
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At 01 FEB 2006 02:13PM Wilhelm Schmitt wrote:
Sprezz,
is the user index the only way to solve the null indexing issue?
I am looking for a way that is less complicated.
Wilhelm
At 01 FEB 2006 02:53PM support@sprezzatura.com wrote:
Well, you could generate the !! code and strip out the write to the transation tables if the corresponding value does not meet your criteria.
support@sprezzatura.com
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At 01 FEB 2006 04:40PM Wilhelm Schmitt wrote:
If I understand then correctly, there is no configuration option available in OI for this case.
Altering the !! code, could that have any drawback, like slower execution or different MFS sequencing (I assume that SI.MFS still goes last)?
Wilhelm
At 01 FEB 2006 05:49PM Aiden Massey wrote:
Might be a good time to organize a peasants revolt to press for the option to exclude null values. This has been an irksome problem since Arev 1.0.
At 02 FEB 2006 01:19AM Warren Auyong wrote:
And the cause of many headaches when rebuilding relational indexes too.
At 02 FEB 2006 02:15AM support@sprezzatura.com wrote:
MFS position doesn't change. In theory the only difference would be the
if len( var ) then….
Otherwise, should be the same code you have.
support@sprezzatura.com
The Sprezzatura Group Web Site
World Leaders in all things RevSoft
At 02 FEB 2006 01:57PM Karen Oland wrote:
Those using the sample user.index (soundex or metaphone), should keep in mind that the trigger character you use must be one you allow to exist in the index. btree.extract helpfully strips out all the delimiters defined for the index before calling your parser module (so, in our case, all the dollar signs and most other punctuation is gone, so the default routine doesn't ever call the compare module defined).