J. Jeff Roberts wrote:
I have a question about indices. If I typically do this: select field1, field2 from table where field3 = 1 but I sometimes do this: select field1 from table where field3 = 1
You have to valuate the additional space for the index and the overhead to keep index actual. I think one index is the better solution.
But be aware that field3 is the first index column.
I have a similar question. I have some queries with are something like: select a.* from table a where a.f1 = x select a.* from table a where a.f1 = x and a.f2 = y select a.* from table a where a.f2 = y and a.f3 = z select a.* from table a where a.f1 = x and a.f2 = y and a.f3 = z ... These queries are automatically generated by the (java) application.
Should I create three individual indexes or one index with many columns? Which is better for performance? Does the number of different values per column make a difference?
Thanks, Arne
-- Institute of Shipping Economics and Logistics http://www.isl.org/ Arne Gehlhaar mailto:[EMAIL PROTECTED] Universitaetsallee GW1 Block A phone:+49.421.22096.49 D-28359 Bremen, Germany fax:+49.421.22096.55
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