创建触发器以在更新表后插入

Question

Create a trigger named trigger_contact_af_update that is triggered whenever the contact table is updated. This trigger will insert the org_name and action into the table contact_log_history after the update of contact details. The action name in the affected log table contact_log_history is 'After_Update_Contact' .

Hints:

• Trigger name : trigger_contact_af_update
• Table name : contact_log_history
• Field names : org_name,action
• Action : 'After_Update_Contact'.

The table structure of contact_log_history is as follows:

org_name Varchar(30)
action Varchar(30)

I wrote the below trigger but no error or trigger created.

CREATE OR REPLACE TRIGGER trigger_contact_af_update AFTER UPDATE 
    ON contact_log_history FOR EACH ROW 
DECLARE 
    org_name VARCHAR(30);
    action VARCHAR(30);
BEGIN 
    if (:new.action == 'After_Update_Contact') 
    then 
        INSERT INTO contact_log_history (org_name, action) 
        values (:new.org_name, :new:action);
    end if ;
END;

Answer 1

You should use

SHOW ERRORS 

or

select * from user_errors;

to check the errors during compilation for procedures/functions/triggers.

Here's a working trigger after fixing the issues and avoiding the variables.

CREATE  OR replace TRIGGER contact_af_update AFTER 
UPDATE 
ON contact FOR EACH ROW 
DECLARE 
BEGIN 
  IF (:new.action = 'After_Update_Contact') THEN 
    INSERT INTO contact_log_history 
                ( 
                            org_name, 
                            action 
                ) 
                VALUES 
                ( 
                            :new.org_name, 
                            :new.action 
                ); 

  END IF ; 
END;
/

Demo