Re: Speeding up guerys

Trond-Eirik Kolloen wrote: > Hello > > I'm developing a MFC app connecting to a informix database by using ODBC. > I'm really fresh in this, so any help will be gladly recived. > This application is using 5 different SQL querys over and over again, but > with different parameters. > > This is function very good, excep when I'm getting to the last guery. > > The querys are like this: (the values of the ? will depend on the previus > query > > select * from language > select * from lang_dep_rep where lang_name = ? > select * from lang_dep_pg where lang_name = ? and rep_num = ? > select * from lang_dep_vg where lang_name = ? and rep_num = ? and pg_num = ?> select* from lang_dep_rub where lang_name = ? and rep_num = ? and pg_num = ? > and vg_num = ? > > Every one of this querys will never return mutch more than 20 records. > Hi What about joins? They will work faster. I didn't try this, but it should be something like: select * from language l, lang_dep_rep r, lang_dep_pg p, lang_dep_vg v,lang_dep_rub u where l.lang_name = r.lang_name and p.lang_name = r.lang_name and p.rep_num = r.rep_num and v.lang_name = p.lang_name and v.rep_num = r.rep_num and v.pg_num = r.pg_num and u.lang_name = v.lang_name and u.rep_num = v.ret_num and u.pg_num = v.pg_num and u.vg_num = v.vg_num Even better if you specify the columns, you really need. Instead fo "select * from ..." you should say "select v.pg_name, u.pg_name from ...". I know it is convenient to say "select *", but it is worth the trouble specifying columns. If Informix-Databas have enough information in his index, he do not even read the data-pages. Tommi M'kitalo Dr. Eckhardt + Partner GmbH