Re: Composite index question

In article <3cb8bf2a.76390599_at_nntp.mindspring.com>, willjamu_at_mindspring.com says...
>
>On Sat, 13 Apr 2002 18:51:36 GMT, "Tintin" <nospam_at_nospam.com> wrote:
>
>This was certainly a bigger issue previous to 9i. You still may wish
>to consider cardinality if you use index compression.
>
>In 9i, IIRC, it is called Skip Scan Indexing or something similar.

Partially there, anyway. Skip scanning of an index means you can still do index scans when you have a composite index and your query doesn't reference the leading columns e.g. in the composite index given below, you can use skip scanning when the query just references B, C or B then C. What you can't use it for is a query that references the columns in a different order e.g. C then B.

>
>In a recent copy of oramag at oramag.com there was discussion on this.
>
>>Learning Oracle 9i. Need some clarification on something.
>>
>>If I create a composite index on columns A, B and C and want to run a SELECT
>>query that uses that index, do I have to specify the columns in the WHERE
>>clause in the same order they are in the index?
>>
>>~ !T
>>
>>
>

HTH. Additions and corrections welcome.

Pete

SELECT standard_disclaimer, witty_remark FROM company_requirements; Received on Sat Apr 13 2002 - 21:42:58 CDT