These triggers demonstrate the use of the :new correlation identifier. : Old New Value « Trigger « Oracle PL / SQL






These triggers demonstrate the use of the :new correlation identifier.

  
SQL>
SQL> CREATE TABLE lecturer (
  2    id               NUMBER(5) PRIMARY KEY,
  3    first_name       VARCHAR2(20),
  4    last_name        VARCHAR2(20),
  5    major            VARCHAR2(30),
  6    current_credits  NUMBER(3)
  7    );

Table created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10001, 'Scott', 'Lawson','Computer Science', 11);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major, current_credits)
  2                VALUES (10002, 'Mar', 'Wells','History', 4);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10003, 'Jone', 'Bliss','Computer Science', 8);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10004, 'Man', 'Kyte','Economics', 8);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10005, 'Pat', 'Poll','History', 4);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10006, 'Tim', 'Viper','History', 4);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10007, 'Barbara', 'Blues','Economics', 7);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10008, 'David', 'Large','Music', 4);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10009, 'Chris', 'Elegant','Nutrition', 8);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10010, 'Rose', 'Bond','Music', 7);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10011, 'Rita', 'Johnson','Nutrition', 8);

1 row created.

SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
  2                VALUES (10012, 'Sharon', 'Clear','Computer Science', 3);

1 row created.

SQL>
SQL>
SQL> CREATE OR REPLACE TRIGGER GenerateStudentID
  2    BEFORE INSERT OR UPDATE ON lecturer
  3    FOR EACH ROW
  4  BEGIN
  5    SELECT 20001
  6      INTO :new.ID
  7      FROM dual;
  8  END GenerateStudentID;
  9  /

Trigger created.

SQL>
SQL> INSERT INTO lecturer (first_name, last_name)
  2    VALUES ('L', 'L');

1 row created.

SQL>
SQL>
SQL>
SQL> select * from lecturer;

        ID FIRST_NAME           LAST_NAME
---------- -------------------- --------------------
MAJOR                          CURRENT_CREDITS
------------------------------ ---------------
     10001 Scott                Lawson
Computer Science                            11

     10002 Mar                  Wells
History                                      4

     10003 Jone                 Bliss
Computer Science                             8


        ID FIRST_NAME           LAST_NAME
---------- -------------------- --------------------
MAJOR                          CURRENT_CREDITS
------------------------------ ---------------
     10004 Man                  Kyte
Economics                                    8

     10005 Pat                  Poll
History                                      4

     10006 Tim                  Viper
History                                      4


        ID FIRST_NAME           LAST_NAME
---------- -------------------- --------------------
MAJOR                          CURRENT_CREDITS
------------------------------ ---------------
     10007 Barbara              Blues
Economics                                    7

     10008 David                Large
Music                                        4

     10009 Chris                Elegant
Nutrition                                    8


        ID FIRST_NAME           LAST_NAME
---------- -------------------- --------------------
MAJOR                          CURRENT_CREDITS
------------------------------ ---------------
     10010 Rose                 Bond
Music                                        7

     10011 Rita                 Johnson
Nutrition                                    8

     10012 Sharon               Clear
Computer Science                             3


        ID FIRST_NAME           LAST_NAME
---------- -------------------- --------------------
MAJOR                          CURRENT_CREDITS
------------------------------ ---------------
     20001 L                    L



13 rows selected.

SQL>
SQL> drop table lecturer;

Table dropped.

   
  








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