Information is transmitted between a PL/SQL program and the database through variables. In many cases, a PL/SQL variable will be used to manipulate data stored in a existing relation.
Every variable has a specific type associated with it. In this case, it is essential that the variable have the same type as the relation column.
The workaround for this is to use variables defined in packages to store information that must be in scope for all timing points.
CASE WHEN INSERTING THEN -- Include any code specific for when the trigger is fired from an INSERT. WHEN UPDATING THEN -- Include any code specific for when the trigger is fired from an UPDATE. WHEN DELETING THEN -- Include any code specific for when the trigger is fired from a DELETE. DML triggers have four basic timing points for a single table. With the exception of Compound Triggers, the triggers for the individual timing points are self contained and can't automatically share state or variable information.
There are optional declaration and exception sections, like any other PL/SQL block, if required.
The "dml-event" can be one or more of the following.
LAST_APPLIED_DATE,'DD-MON-YYYY'))/12 INTO years_since_last_applied FROM dual; -- Check whether years_since_last_applied is greater than 2 years or not IF (years_since_last_applied -- setting date format to to 'DD-MON-YYYY' alter session set nls_date_format = 'DD-MON-YYYY'; INSERT INTO job_openings VALUES (1,'Mark','Sharma',10,'01-JAN-2012'); INSERT INTO job_openings VALUES (2,'Praveen','Kumar',4,'01-DEC-2010'); INSERT INTO job_openings VALUES (3,'Rahul','Kohli',6,null); -- output 1 rows inserted. TRG_BEFORE_EMP_UPDATE' -- Try to update last_Applied_Date which is less than 2 years UPDATE job_openings SET LAST_APPLIED_DATE = '10-JUN-2016' where APPLICATION_ID = 3; -- error Error report - ORA-20000: Previous application attempt must not be done in last 2 years. TRG_BEFORE_EMP_UPDATE", line 15 ORA-04088: error during execution of trigger 'SYSTEM. UPDATED_DATE := sysdate; END; -- setting date format to to 'DD-MON-YYYY' alter session set nls_date_format = 'DD-MON-YYYY'; INSERT INTO person_records VALUES (101,'Devil','Khedut',sysdate,null,null); INSERT INTO person_records VALUES (102,'Kanji','Yadav',sysdate,null,null); -- output 1 rows inserted. CREATE TABLE bank_transactions_audit ( TXN_ID number(10), TXN_NUMBER varchar2(20), PARTY_NAME varchar2(50), TXN_DATE date, CREATED_BY varchar2(20), CREATED_DATE date ); --Creating Trigger CREATE OR REPLACE TRIGGER trg_before_update_txn_audit BEFORE UPDATE ON bank_transactions FOR EACH ROW BEGIN -- Insert OLD values in audit table for logging purpose INSERT INTO bank_transactions_audit VALUES(: OLD.
TRG_BEFORE_EMP_UPDATE' --Creating person_records table. CREATE TABLE person_records ( PERSON_ID number(10) primary key, FIRST_NAME varchar2(50), LAST_NAME varchar2(50), HIRE_DATE date, UPDATED_BY varchar2(20), UPDATED_DATE date ); CREATE OR REPLACE TRIGGER trg_before_person_update BEFORE UPDATE on person_records FOR EACH ROW DECLARE username varchar2(20); BEGIN SELECT USER INTO username FROM dual; -- Setting updated_by and updated_Date values.