Our developers store XML docuements inside CLOBS and want to search the CLOB contents based on a search string. I have lot of concern about such queries but could benefit from someone on the list who has already solved the performnce issues with such searches.
Typical existing queries I have come across are: Select columns FROM list of tables WHERE join conditions AND UPPER(tab1.varcharcol) LIKE '%:in_string%' OR UPPER(tab2.varcharcol) LIKE '%:in_string%' OR ..... OR dbms_lob.instr(lobcol,:in_string,1,1) <> 0; Note: in_string is always upper case but the columns are Concerns: 1. Poor index selection due to UPPER 2. CLOB searches are obviously wrong. To do a mixed case string match one needs to read chunks of the lob in a user defined function of some sort, convert it to upper and then do string matches. Any tips on this one? ===== Sundeep Maini Consultant Currently on Assignement at Marshfield Clinic WI [EMAIL PROTECTED] __________________________________________________ Do You Yahoo!? Great stuff seeking new owners in Yahoo! Auctions! http://auctions.yahoo.com -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: sundeep maini INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
