Re: using index

I want some standards or guidelines in designing database and programming in SQL. I think there should be some standard mechanisms in forming the execution path of the SQL query. When writing program spec., I don't have the database in mind, maybe it could be IBM DB2, CA-Ingres, or Oracle Rdb.

Karen Paulsell (karenp_at_sybase.com) wrote:
: So, you're still posting these questions to the Sybase, Microsoft, and
: Oracle comp.databases groups. Do you need answers for all three? Or
: are you asking about 1 or 2 of them?
:
: In article <6vskis$q86$1_at_imsp009a.netvigator.com> paulkcng_at_news.netvigator.com (Ng K C Paul) writes:
: >What about if I have an index with 2 columns (dept_no,emp_no)?
: >
: >My where clause is something like this:
: >
: >where dept_no = 10
: >and emp_no <> 0
: >
: >fumi (fumi__at_tpts5.seed.net.tw) wrote:
: >:
: >: Ng K C Paul ¼¶¼g©ó¤å³¹ <6vjqth$7dg$1_at_imsp009a.netvigator.com>...
: >: >Is is always true that in the where clause column with Not Equal(<>) will
: >: >not use index?
: >:
: >: Yes. It's usually WORTHLESS to use index if there is just one "not equal"
: >: condition in the where clause.
: >:
: >:
: >:
:
:
  Received on Tue Oct 13 1998 - 00:00:00 CDT