Re: Cursors

Wow! I tried everything but this, but it works! Thanks! Phil Bill Ennis wrote: > Hi, > > Append "FOR UPDATE" onto the end of the $select_statement string. > > -Bill > } > } Art S. Kagel wrote: > } > } > Nils' suggestion is excellent, however, it does not protect your users > } > from overwriting data changed by others while he/she is editing the > } > current record, as Nils points out. Immediately before updating the > } > record you should FETCH the row that you are about to update with a > } > CURSOR...FOR UPDATE so that the row is locked and compare the values > } > returned for all columns, or for an indicative column like a timestamp > } > or update count, to the original values that you FETCHED. Then only if > } > the values have not changed UPDATE ... WHERE CURRENT OF <cursorname of > } > cursor for update>. This will give you the safety of locking rows but > } > permits greater concurrency since the lock in only momentary. > } > } Perhaps you can help me with with doing this in ESQL/C. > } > } I'd like to do something like: > } > } $ prepare select_id from $select_statement; > } > } $ describe select_id into in_vals; > } > } $ declare sel_cursor cursor for select_id for update; > } > } $ prepare update_id from "update set column1 = ? where current of > } sel_cusor; > } > } $ execute update_id using in_vals; > } > } > } The problem is that $declare will not let me use a prepared statement id > } with the > } "for update" keywords. Thus I cannot dynamically set the "select cursor for > } update". > } > } Any ideas on how to do this? > } > } Phil > } > } -- > } -------------------------------------------------------------------------- > } Philip Walden > } Hewlett Packard > } Supply Chain Information Systems > } 1501 Page Mill Road, M/S 5L-A > } Palo Alto, CA 94304 > } (415) 857-3899 FAX (415) 857-8234 > } http://www.pgis.hp.com/~pwalden > } mailto:phil_walden@hp.com > } -------------------------------------------------------------------------- > } > } > } > } > > -- > Bill Ennis Voice: 312-474-7516 > SSA Fax: 312-474-7460 > 500 W. Madison email: ennis@ssax.com ennis@accesschicago.net -- -------------------------------------------------------------------------- Philip Walden Hewlett Packard Supply Chain Information Systems 1501 Page Mill Road, M/S 5L-A Palo Alto, CA 94304 (415) 857-3899 FAX (415) 857-8234 http://www.pgis.hp.com/~pwalden mailto:phil_walden@hp.com --------------------------------------------------------------------------