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Categories / Oracle PLSQL Tutorial / Trigger

 

Trigger Which Modifies a Mutating Table

SQL> 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> 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 4 rows selected. SQL> SQL> CREATE OR REPLACE TRIGGER LimitSalary   2    BEFORE INSERT OR UPDATE OF salary ON employee   3    FOR EACH ROW   4  DECLARE   5    v_MaxSalary CONSTANT NUMBER := 2000;   6    v_CurrentSalary NUMBER;   7  BEGIN   8    SELECT salary   9      INTO v_CurrentSalary  10      FROM employee  11      WHERE id = :new.id;  12  13    IF v_CurrentSalary > v_MaxSalary THEN  14      RAISE_APPLICATION_ERROR(-20000, 'Too high in salary ' || :new.id);  15    END IF;  16  END LimitSalary;  17  / Trigger created. SQL> 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  / insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,               Salary,  City,       Description)             * ERROR at line 1: ORA-01403: no data found ORA-06512: at "RNTSOFT.LIMITSALARY", line 5 ORA-04088: error during execution of trigger 'RNTSOFT.LIMITSALARY' 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  / insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,               Salary, City,        Description)             * ERROR at line 1: ORA-01403: no data found ORA-06512: at "RNTSOFT.LIMITSALARY", line 5 ORA-04088: error during execution of trigger 'RNTSOFT.LIMITSALARY' 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  / insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,               Salary, City,        Description)             * ERROR at line 1: ORA-01403: no data found ORA-06512: at "RNTSOFT.LIMITSALARY", line 5 ORA-04088: error during execution of trigger 'RNTSOFT.LIMITSALARY' 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  / insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,               Salary, City,        Description)             * ERROR at line 1: ORA-01403: no data found ORA-06512: at "RNTSOFT.LIMITSALARY", line 5 ORA-04088: error during execution of trigger 'RNTSOFT.LIMITSALARY' SQL> SQL> select * from employee; 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 4 rows selected. SQL> SQL> -- clean the table SQL> drop table Employee   2  / Table dropped. SQL>