Oracle-L: Re: Do triggers cause a context switch between SQL & PL/SQL

From: <Jared.Still_at_radisys.com>
Date: Tue, 01 Apr 2003 10:19:37 -0800
Message-ID: <F001.00577423.20030401101937@fatcity.com>

Since you the action switches from SQL to PL/SQL to enforce the trigger, it sounds like a context switch to me.

FYI: This can be improved somewhat by adding "and rownum < 2 " into the WHERE clauses of these. There will be noticable improvement when there are many child rows.

Jared

DEEDSD_at_Nationwide.com
Sent by: root_at_fatcity.com
04/01/2003 09:48 AM
Please respond to ORACLE-L

        To:     Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
        cc: 
        Subject:        Do triggers cause a context switch between SQL & PL/SQL

Question:

If some idiot decides to circumvent Oracle's referential integrity and re-implement it by using triggers (insert, update, delete) that checks the foreign (parent/child) key fields in other tables like this,

declare numrows INTEGER;
begin

ApplicationForm is used if the state and other criteria match that in
ApplicationFormCriteria ON PARENT DELETE RESTRICT select count(*) into numrows from ApplicationFormCriteria where ApplicationFormCriteria.applicationFormId = :old.applicationFormId; if (numrows > 0) then raise_application_error( -20343, 'Database Integrity Violation - Cannot DELETE row in Table ''ApplicationForm'' because referencing row exists in table ''ApplicationFormCriteria'' for Primary Key (applicationFormId)=' || :old.applicationFormId ); end if;

end;

would it cause context switching between the SQL & PL/SQL engines?

Yes, some genius did this in one of our databases. Two hundred third/fourth normal form tables enforced by 800 triggers... I have him registered to be stoned in public.

--

Please see the official ORACLE-L FAQ: http://www.orafaq.net
--

Author:
INET: DEEDSD_at_Nationwide.com

Fat City Network Services    -- 858-538-5051 http://www.fatcity.com
San Diego, California        -- Mailing list and web hosting services
---------------------------------------------------------------------

To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (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).

--

Please see the official ORACLE-L FAQ: http://www.orafaq.net
--

Author:
INET: Jared.Still_at_radisys.com

Fat City Network Services    -- 858-538-5051 http://www.fatcity.com
San Diego, California        -- Mailing list and web hosting services
---------------------------------------------------------------------