Re: Setting Dirty Reads or No Lock for SELECT

In article <C3E31780D570D4119FBF00B0D0208309B52ADE_at_RO>, WLau_at_Collegeboard.org says...
>
>How can you indicate to the SELECT statement to not put a lock on a table
>while you are reading from it. This is important for me when doing long
>queries on an Oracle database. DB2 had a "WITH UR" option and SQL Server
>has a "NO LOCK" option. Sorry for the novice question, but just started to
>use Oracle. Doh! Thanks. Later...
>
>

no need.

Readers do not block writers in Oracle.
Writers do not block readers in Oracle.

there are no shared read locks in Oracle. An exclusive lock on a row does not cause your query to stop dead in its tracks (nor do we do a "dirty" read to get an incorrect answer)

A reader will not conflict with a writer and vice versa. No need to concern your self with "dirty reads" -- just not needed.

See
http://technet.oracle.com/doc/oracle8i_816/server.816/a76965/c23cnsis.htm#2570

you might want to do a read through on that entire manual (server concepts). It will give you a good overview of what you are now working with.

>- Wayne
>
>
>
>
>
>
>--
>Posted from cb4nyo.collegeboard.org [207.122.6.3]
>via Mailgate.ORG Server - http://www.Mailgate.ORG

Thomas Kyte (tkyte_at_us.oracle.com) Oracle Service Industries Howtos and such: http://asktom.oracle.com/ http://asktom.oracle.com/~tkyte/ Oracle Magazine: http://www.oracle.com/oramag Opinions are mine and do not necessarily reflect those of Oracle Corp Received on Wed May 30 2001 - 16:00:45 CDT