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2010-05-26T13:45:19Z

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2010-05-26T09:58:25Z

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==Create an after delete trigger==



<source lang="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> create table employee_audit (
2 id VARCHAR2(4 BYTE),
3 salary Number(8,2),
4 delete_date Date,
5 deleted_by VARCHAR2(15 BYTE)
6 )
7 /
Table created.
SQL>
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>
SQL>
SQL>
SQL>
SQL>
SQL> CREATE OR REPLACE TRIGGER employee_after_delete
2 AFTER DELETE
3 ON employee
4 FOR EACH ROW
5
6 DECLARE
7 v_username varchar2(10);
8
9 BEGIN
10
11 -- Find username of person performing the DELETE on the table
12 SELECT user INTO v_username
13 FROM dual;
14
15 -- Insert record into audit table
16 INSERT INTO employee_audit (id, salary, delete_date, deleted_by)
17 VALUES ( :old.id, :old.salary, sysdate, v_username );
18
19 END;
20 /
Trigger created.
SQL>
SQL> delete from employee;
8 rows deleted.
SQL>
SQL> select * from employee_audit;
ID SALARY DELETE_DA DELETED_BY
---- ---------- --------- ---------------
01 1234.56 09-SEP-06 sqle
02 6661.78 09-SEP-06 sqle
03 6544.78 09-SEP-06 sqle
04 2344.78 09-SEP-06 sqle
05 2334.78 09-SEP-06 sqle
06 4322.78 09-SEP-06 sqle
07 7897.78 09-SEP-06 sqle
08 1232.78 09-SEP-06 sqle
8 rows selected.
SQL>
SQL> drop table employee_audit;
Table dropped.
SQL>
SQL>
SQL>
SQL> -- clean the table
SQL> drop table Employee
2 /
Table dropped.
SQL>
SQL>

</source>

==This is an example of a DML trigger.==



<source lang="sql">

SQL>
SQL> CREATE TABLE major_stats (
2 major VARCHAR2(30),
3 total_credits NUMBER,
4 total_students NUMBER);
Table created.
SQL>
SQL> INSERT INTO major_stats (major, total_credits, total_students) VALUES ("Computer Science", 22, 3);
1 row created.
SQL>
SQL> INSERT INTO major_stats (major, total_credits, total_students) VALUES ("History", 12, 3);
1 row created.
SQL>
SQL> INSERT INTO major_stats (major, total_credits, total_students) VALUES ("Economics", 15, 2);
1 row created.
SQL>
SQL> INSERT INTO major_stats (major, total_credits, total_students) VALUES ("Music", 11, 2);
1 row created.
SQL>
SQL> INSERT INTO major_stats (major, total_credits, total_students) VALUES ("Nutrition", 16, 2);
1 row created.
SQL>
SQL>
SQL> CREATE TABLE students (
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>
SQL> CREATE OR REPLACE TRIGGER UpdateMajorStats
2 AFTER INSERT OR DELETE OR UPDATE ON students
3 DECLARE
4 CURSOR c_Statistics IS
5 SELECT major, COUNT(*) total_students,
6 SUM(current_credits) total_credits
7 FROM students
8 GROUP BY major;
9 BEGIN
10 DELETE FROM major_stats;
11
12 FOR v_StatsRecord in c_Statistics LOOP
13 INSERT INTO major_stats (major, total_credits, total_students)
14 VALUES (v_StatsRecord.major, v_StatsRecord.total_credits,
15 v_StatsRecord.total_students);
16 END LOOP;
17 END UpdateMajorStats;
18 /
Trigger created.
SQL>
SQL> INSERT INTO students (id, first_name, last_name, major,current_credits)
2 VALUES (10001, "Scott", "Lawson","Computer Science", 11);
1 row created.
SQL>
SQL> INSERT INTO students (id, first_name, last_name, major, current_credits)
2 VALUES (10002, "Mar", "Wells","History", 4);
1 row created.
SQL>
SQL> INSERT INTO students (id, first_name, last_name, major,current_credits)
2 VALUES (10003, "Jone", "Bliss","Computer Science", 8);
1 row created.
SQL>
SQL> INSERT INTO students (id, first_name, last_name, major,current_credits)
2 VALUES (10004, "Man", "Kyte","Economics", 8);
1 row created.
SQL>
SQL> INSERT INTO students (id, first_name, last_name, major,current_credits)
2 VALUES (10005, "Pat", "Poll","History", 4);
1 row created.
SQL>
SQL> INSERT INTO students (id, first_name, last_name, major,current_credits)
2 VALUES (10006, "Tim", "Viper","History", 4);
1 row created.
SQL>
SQL> INSERT INTO students (id, first_name, last_name, major,current_credits)
2 VALUES (10007, "Barbara", "Blues","Economics", 7);
1 row created.
SQL>
SQL> INSERT INTO students (id, first_name, last_name, major,current_credits)
2 VALUES (10008, "David", "Large","Music", 4);
1 row created.
SQL>
SQL> INSERT INTO students (id, first_name, last_name, major,current_credits)
2 VALUES (10009, "Chris", "Elegant","Nutrition", 8);
1 row created.
SQL>
SQL> INSERT INTO students (id, first_name, last_name, major,current_credits)
2 VALUES (10010, "Rose", "Bond","Music", 7);
1 row created.
SQL>
SQL> INSERT INTO STUDENTS (id, first_name, last_name, major,current_credits)
2 VALUES (10011, "Rita", "Johnson","Nutrition", 8);
1 row created.
SQL>
SQL> INSERT INTO students (id, first_name, last_name, major,current_credits)
2 VALUES (10012, "Sharon", "Clear","Computer Science", 3);
1 row created.
SQL>
SQL> select * from major_stats;
MAJOR TOTAL_CREDITS TOTAL_STUDENTS
------------------------------ ------------- --------------
Computer Science 22 3
Economics 15 2
Nutrition 16 2
History 12 3
Music 11 2
SQL>
SQL> drop table students;
Table dropped.
SQL> drop table major_stats;
Table dropped.
</source>

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Oracle PL/SQL/Trigger/After Delete Trigger - История изменений

в 13:45, 26 мая 2010

Admin: 1 версия