EXPLAIN is an SQL qualifier to aid in query optimisation. It's "commonly" used in the the SQL 'world'.
It is document in the UV SQL Reference guide (sqlref.pdf). It is provides similar functionality to that of other DBMS, to assist you with SQL query optimisation. As UniVerse has two native query languages, but one database engine - it's available for SQL and non-SQL queries. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of john reid Sent: Thursday, October 18, 2007 6:26 AM To: [email protected] Subject: Re: [U2] Indexing & Optimization It appears that 'EXPLAIN' is somewhat documented via an internet search, implying that it might be standard equipment for at least some SQL's in order to show query plans. I did find a file on our system named SQL.HELP. A search revealed 6 records containing 'EXPLAIN' but it also contained a lot of repetition. There was no occurrence in SYS.HELP that I found. The EXPLAIN seemed to show the same thing whether I used a Universe uniquery or an SQL statement, given the same search criteria. On 10/17/07, Jef Lee <[EMAIL PROTECTED]> wrote: > Could someone please explain the EXPLAIN results? The Help does not > show about EXPLAIN. > > In particular, what does the index processing point out? I have 43,000 > records that have A8="DRJ" but only a handful that will have A50="70" so > if I can get the SELECT to use A50 first that would be great. I can see > that additional WITHs make a difference but is the order in the command > significant? > > > > Also is there anything undocumented like EXPLAIN that will tell me how > long a TCL command takes to execute? ------- u2-users mailing list [email protected] To unsubscribe please visit http://listserver.u2ug.org/
