Differences between MySQL and Oracle's triggers and stored procedure syntax

Corrected a script, encountered some of the differences between the two databases, recorded:

Trigger:

Difference	Mysql	ORACLE	Description
Create statements different	Create Trigger ' AA ' before INSERT on ' BB ' For each row	Create or replace trigger AA before insert or update or delete on BB For each row	1.Oracle can trigger the Insert,delete,update event on a trigger. MySQL each trigger supports only one event. In other words, each trigger needs to be split into 3 MySQL trigger at present.
Referencing new and old data is different	Access to new data : Neo AA Get old data : oidbb	Getting new data : : NewAA Get old data : : older. BB	1.oracle multiple pairs of colons

Stored procedures:

Difference	Mysql	ORACLE	Description
Create statements different	DROP PROCEDURE IF EXISTS ' sd_user_p_add_usr '; CREATE PROCEDURE AA( AA varchar (+))	Create or Replace procedure AA( varchar AA) is	1.oracle creation is relatively concise, MySQL must first execute the drop 2.mysql first variable re-type, Oracle opposite, and does not have to limit length 3. If you are number or VARCHAR2, you do not need to define the length. Otherwise the compilation cannot pass
Exception handling not the same	DECLARE EXIT HANDLER for Aaexception BEGIN ... END;	EXCEPTION When OTHERS Then ROLLBACK; ....	1.mysql You cannot customize exceptions, and you need to define them when using internal exceptions
Calls are stored in different ways	Call procedure ();	procedure ();	1. Different calling methods

So how to willful delete triggers:

Declare
V_num number;

BEGIN

Select COUNT (0) into V_num from user_triggers where trigger_name = ' AA '; (Note case)

If V_num > 0 Then
Execute immediate ' DROP TRIGGER AA ';
End If;

END;

Differences between MySQL and Oracle's triggers and stored procedure syntax