Oracle trigger where clause updating htdating com
S_ID = 0 ; END IF; END; To invoke a shell command from a trigger I used a roundabout approach, write to a predefined folder using trigger code 'select into outfile', and famd to monitor that folder, which triggers a php script.[ shell from My SQL trigger] Continuing on the theme of how to emulate STOP ACTION, I wrote this code:delimiter $$DROP TABLE IF EXISTS blocked_insert_message $$CREATE TABLE blocked_insert_message ( unique_error_msg VARCHAR(330) NOT NULL, UNIQUE KEY `unique_error_msg` (`unique_error_msg`)) $$DROP PROCEDURE IF EXISTS die_with_error $$CREATE PROCEDURE die_with_error(msg varchar(300))COMMENT ' Call this to STOP ACTION with a message.' MODIFIES SQL DATA BEGIN DECLARE ts DATETIME DEFAULT NOW(); DECLARE txt VARCHAR(300) DEFAULT msg; DECLARE uniq VARCHAR(330) DEFAULT (SELECT CONCAT(ts, ': ', txt)); -- Run it twice to throw as an error.
INSERT INTO blocked_insert_message VALUES (uniq); INSERT INTO blocked_insert_message VALUES (uniq); END $$delimiter ; When called from a trigger with "call die_with_error('test test test test');" the result is an error like this: ERROR 1062 (23000) at line 1: Duplicate entry '2010-11-13 : test test test test' for key 'unique_error_msg' The clear benefit is that the error message will be thrown reliably and contain arbitrary (though short) free text.
In that case i wanted to prevent the INSERT by causing a deliberate error in the form of updating a non-existing table.
This is what my attempt looked like: CREATE TRIGGER sanity Check BEFORE INSERT ON some Table FOR EACH ROW BEGIN CALL do Sanity Check(@result Bool, @result Message); IF @result Bool = 0 THEN UPDATE There Was An Error_Call_privilege Sanity Check_To View The Error SET There Was='an error'; END IF; END;//While mysql allows the trigger even though the table doesn't exist, it will _always_ complain (throw an error) when it executes the trigger, even if @result Bool = 1. The suggestion of Nicolas LESCURE does work in combination with the IF-statement On Stop Action problems.
For example, if you're deleting a row and this action activates a trigger, is not possible to abort the proccess of DELETE of the row.
A way to abort the current operation, is to cause a deliberated error.
This also enables you to use the same statements that are permitted within stored routines. Within the trigger body, you can refer to columns in the subject table (the table associated with the trigger) by using the aliases to lock a table that has triggers, the tables used within the trigger are also locked, as described in Section 188.8.131.52, “LOCK TABLES and Triggers”.