Reference old and new value by column in a before update Trigger : Old New Value « Trigger « Oracle PL / SQL






Reference old and new value by column in a before update Trigger

 


SQL> -- create demo table
SQL> create table Employee(
  2    ID                 VARCHAR2(4 BYTE)         NOT NULL,
  3    First_Name         VARCHAR2(10 BYTE),
  4    Last_Name          VARCHAR2(10 BYTE),
  5    Start_Date         DATE,
  6    End_Date           DATE,
  7    Salary             Number(8,2),
  8    City               VARCHAR2(10 BYTE),
  9    Description        VARCHAR2(15 BYTE)
 10  )
 11  /

Table created.

SQL>
SQL> -- prepare data
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2               values ('01','Jason',    'Martin',  to_date('19960725','YYYYMMDD'), to_date('20060725','YYYYMMDD'), 1234.56, 'Toronto',  'Programmer')
  3  /

1 row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values('02','Alison',   'Mathews', to_date('19760321','YYYYMMDD'), to_date('19860221','YYYYMMDD'), 6661.78, 'Vancouver','Tester')
  3  /

1 row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values('03','James',    'Smith',   to_date('19781212','YYYYMMDD'), to_date('19900315','YYYYMMDD'), 6544.78, 'Vancouver','Tester')
  3  /

1 row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values('04','Celia',    'Rice',    to_date('19821024','YYYYMMDD'), to_date('19990421','YYYYMMDD'), 2344.78, 'Vancouver','Manager')
  3  /

1 row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values('05','Robert',   'Black',   to_date('19840115','YYYYMMDD'), to_date('19980808','YYYYMMDD'), 2334.78, 'Vancouver','Tester')
  3  /

1 row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary, City,        Description)
  2                values('06','Linda',    'Green',   to_date('19870730','YYYYMMDD'), to_date('19960104','YYYYMMDD'), 4322.78,'New York',  'Tester')
  3  /

1 row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary, City,        Description)
  2                values('07','David',    'Larry',   to_date('19901231','YYYYMMDD'), to_date('19980212','YYYYMMDD'), 7897.78,'New York',  'Manager')
  3  /

1 row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary, City,        Description)
  2                values('08','James',    'Cat',     to_date('19960917','YYYYMMDD'), to_date('20020415','YYYYMMDD'), 1232.78,'Vancouver', 'Tester')
  3  /

1 row created.

SQL>
SQL>
SQL>
SQL> -- display data in the table
SQL> select * from Employee
  2  /

ID   FIRST_NAME LAST_NAME  START_DAT END_DATE      SALARY CITY       DESCRIPTION
---- ---------- ---------- --------- --------- ---------- ---------- ---------------
01   Jason      Martin     25-JUL-96 25-JUL-06    1234.56 Toronto    Programmer
02   Alison     Mathews    21-MAR-76 21-FEB-86    6661.78 Vancouver  Tester
03   James      Smith      12-DEC-78 15-MAR-90    6544.78 Vancouver  Tester
04   Celia      Rice       24-OCT-82 21-APR-99    2344.78 Vancouver  Manager
05   Robert     Black      15-JAN-84 08-AUG-98    2334.78 Vancouver  Tester
06   Linda      Green      30-JUL-87 04-JAN-96    4322.78 New York   Tester
07   David      Larry      31-DEC-90 12-FEB-98    7897.78 New York   Manager
08   James      Cat        17-SEP-96 15-APR-02    1232.78 Vancouver  Tester

8 rows selected.

SQL>
SQL> -- BEFORE UPDATE Trigger
SQL>     CREATE OR REPLACE TRIGGER employee_before_update
  2      BEFORE UPDATE
  3          ON employee
  4          FOR EACH ROW
  5
  6      DECLARE
  7          v_username varchar2(10);
  8
  9      BEGIN
 10          -- Find username of person performing UPDATE on the table
 11          SELECT user INTO v_username
 12          FROM dual;
 13
 14          dbms_output.put_line('By: '||v_username);
 15          dbms_output.put_line('Date: '||sysdate);
 16          dbms_output.put_line(':new.id: '||:new.id);
 17          dbms_output.put_line(':new.first_name: '||:new.first_name);
 18          dbms_output.put_line(':new.last_name: '||:new.last_name);
 19          dbms_output.put_line(':old.id: '||:old.id);
 20          dbms_output.put_line(':old.first_name: '||:old.first_name);
 21          dbms_output.put_line(':old.last_name: '||:old.last_name);
 22
 23      END;
 24      /

Trigger created.

SQL>
SQL> update employee set first_name='newName';
By: JAVA2S
Date: 09-SEP-06
:new.id: 01
:new.first_name: newName
:new.last_name: Martin
:old.id: 01
:old.first_name: Jason
:old.last_name: Martin
By: JAVA2S
Date: 09-SEP-06
:new.id: 02
:new.first_name: newName
:new.last_name: Mathews
:old.id: 02
:old.first_name: Alison
:old.last_name: Mathews
By: JAVA2S
Date: 09-SEP-06
:new.id: 03
:new.first_name: newName
:new.last_name: Smith
:old.id: 03
:old.first_name: James
:old.last_name: Smith
By: JAVA2S
Date: 09-SEP-06
:new.id: 04
:new.first_name: newName
:new.last_name: Rice
:old.id: 04
:old.first_name: Celia
:old.last_name: Rice
By: JAVA2S
Date: 09-SEP-06
:new.id: 05
:new.first_name: newName
:new.last_name: Black
:old.id: 05
:old.first_name: Robert
:old.last_name: Black
By: JAVA2S
Date: 09-SEP-06
:new.id: 06
:new.first_name: newName
:new.last_name: Green
:old.id: 06
:old.first_name: Linda
:old.last_name: Green
By: JAVA2S
Date: 09-SEP-06
:new.id: 07
:new.first_name: newName
:new.last_name: Larry
:old.id: 07
:old.first_name: David
:old.last_name: Larry
By: JAVA2S
Date: 09-SEP-06
:new.id: 08
:new.first_name: newName
:new.last_name: Cat
:old.id: 08
:old.first_name: James
:old.last_name: Cat

8 rows updated.

SQL>
SQL>
SQL> -- clean the table
SQL> drop table Employee
  2  /

Table dropped.

SQL>
           
         
  








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