Choosing the right index in a SELECT statement 1

[GEBOF]

Hi,

A table has an index on two fields (not the unique index).
When selecting data using the fields of the index the system performs a sequential scan.

Can I tell informix to use the index I want it to Use ?


Thanks

 

[GRP]

The select statemnt which use should have the same key sequence, then the informix will automaticaly refer to the related index. For E.g:

If you have two indexes one on emp_code field and the other one on grade_code.

The select statment

select * from employee_mast
where emp_code = "1057";

will refer the emp_code index. If you want to refer to all the rows of a select statemnt, you can specifiy some query which selects all the rows like this
where emp_code matches "*";


G.R.P.

 

[GEBOF]

Thanks for helping out.

I've Updateted the statistics of the table and now the select statement chooses the right index.

Gebof