Oracle PL/SQL/PL SQL/Your own Exception
Содержание
Define and use your own exception
<source lang="sql">
SQL> SQL> -- define and use your own exception SQL> SQL> SQL> declare
2 CHILD_ERROR exception; 3 begin 4 raise CHILD_ERROR; 5 end; 6 / declare
ERROR at line 1: ORA-06510: PL/SQL: unhandled user-defined exception ORA-06512: at line 4
SQL>
</source>
Handling a user-defined exception
<source lang="sql">
SQL> SQL> CREATE TABLE session (
2 department CHAR(3), 3 course NUMBER(3), 4 description VARCHAR2(2000), 5 max_lecturer NUMBER(3), 6 current_lecturer NUMBER(3), 7 num_credits NUMBER(1), 8 room_id NUMBER(5) 9 );
Table created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("HIS", 101, "History 101", 30, 11, 4, 20000);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("HIS", 301, "History 301", 30, 0, 4, 20004);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("CS", 101, "Computer Science 101", 50, 0, 4, 20001);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("ECN", 203, "Economics 203", 15, 0, 3, 20002);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("CS", 102, "Computer Science 102", 35, 3, 4, 20003);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("MUS", 410, "Music 410", 5, 4, 3, 20005);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("ECN", 101, "Economics 101", 50, 0, 4, 20007);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("NUT", 307, "Nutrition 307", 20, 2, 4, 20008);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("MUS", 100, "Music 100", 100, 0, 3, NULL);
1 row created. SQL> SQL> SQL> CREATE TABLE myLogTable (
2 code NUMBER, 3 message VARCHAR2(200), 4 info VARCHAR2(100) 5 );
Table created. SQL> SQL> SQL> DECLARE
2 myException EXCEPTION;
3 studentCount NUMBER(3);
4 studentMax NUMBER(3);
5 BEGIN
6 SELECT current_lecturer, max_lecturer
7 INTO studentCount, studentMax
8 FROM session
9 WHERE department = "HIS" AND course = 101;
10 IF studentCount > studentMax THEN
11 RAISE myException;
12 END IF;
13 EXCEPTION
14 WHEN myException THEN
15 INSERT INTO myLogTable (info) VALUES ("History 101 has " || studentCount ||
16 "lecturer: max allowed is " || studentMax);
17 END;
18 /
PL/SQL procedure successfully completed. SQL> SQL> drop table myLogTable; Table dropped. SQL> SQL> drop table session; Table dropped.
</source>
How to define your own exception
<source lang="sql">
SQL> SQL> SQL> -- User defined exception SQL> SQL> begin
2 declare --start of nested block
3 NESTED_EXCEPTION exception;
4 begin
5 raise NESTED_EXCEPTION;
6 end; --end of nested block
7 exception
8 when NESTED_EXCEPTION then
9 dbms_output.put_line("NESTED_EXCEPTION caught!");
10 end;
11 /
when NESTED_EXCEPTION then
*
ERROR at line 8: ORA-06550: line 8, column 10: PLS-00201: identifier "NESTED_EXCEPTION" must be declared ORA-06550: line 0, column 0: PL/SQL: Compilation unit analysis terminated
SQL> SQL>
</source>
Insert Exception message to an audit table
<source lang="sql">
SQL> -- log exception to log SQL> SQL> 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> CREATE OR REPLACE PROCEDURE add_new_employee
2 (employee_id_in IN NUMBER, salary_in IN NUMBER) 3 IS 4 no_salary EXCEPTION; 5 6 BEGIN 7 IF salary_in = 0 THEN 8 RAISE no_salary; 9 ELSE 10 INSERT INTO employee (id, salary ) VALUES ( employee_id_in, salary_in ); 11 END IF; 12 13 EXCEPTION 14 WHEN no_salary THEN 15 raise_application_error (-20001,"You must have salary in order to insert the employee."); 16 17 18 19 20 END; 21 /
Procedure created. SQL> SQL> exec add_new_employee("99",0); BEGIN add_new_employee("99",0); END;
ERROR at line 1: ORA-20001: You must have salary in order to insert the employee. ORA-06512: at "sqle.ADD_NEW_EMPLOYEE", line 15 ORA-06512: at line 1
SQL> SQL> -- clean the table SQL> drop table Employee
2 /
Table dropped. SQL>
</source>
Raise User-defined exceptions
<source lang="sql">
SQL> SQL> SQL> SQL> DECLARE
2 myException EXCEPTION;
3 BEGIN
4
5 RAISE myException;
6
7 DBMS_OUTPUT.PUT_LINE("This enrollment has been deleted");
8 EXCEPTION
9
10 WHEN myException THEN
11 DBMS_OUTPUT.PUT_LINE("This enrollment is already confirmed");
12 DBMS_OUTPUT.PUT_LINE("It cannot be deleted");
13 END;
14
15 /
This enrollment is already confirmed It cannot be deleted PL/SQL procedure successfully completed. SQL>
</source>
used defined exception
<source lang="sql">
SQL> SQL> declare
2 NESTED_EXCEPTION exception;
3 begin
4
5 raise NESTED_EXCEPTION;
6
7 exception
8
9 when NESTED_EXCEPTION then
10 dbms_output.put_line("NESTED_EXCEPTION caught!");
11 end;
12 /
NESTED_EXCEPTION caught! PL/SQL procedure successfully completed. SQL> SQL>
</source>
Using SQLCODE and SQLERRM
<source lang="sql">
SQL> SQL> CREATE TABLE session (
2 department CHAR(3), 3 course NUMBER(3), 4 description VARCHAR2(2000), 5 max_lecturer NUMBER(3), 6 current_lecturer NUMBER(3), 7 num_credits NUMBER(1), 8 room_id NUMBER(5) 9 );
Table created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("HIS", 101, "History 101", 30, 11, 4, 20000);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("HIS", 301, "History 301", 30, 0, 4, 20004);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("CS", 101, "Computer Science 101", 50, 0, 4, 20001);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("ECN", 203, "Economics 203", 15, 0, 3, 20002);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("CS", 102, "Computer Science 102", 35, 3, 4, 20003);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("MUS", 410, "Music 410", 5, 4, 3, 20005);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("ECN", 101, "Economics 101", 50, 0, 4, 20007);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("NUT", 307, "Nutrition 307", 20, 2, 4, 20008);
1 row created. SQL> SQL> INSERT INTO session(department, course, description, max_lecturer, current_lecturer, num_credits, room_id)
2 VALUES ("MUS", 100, "Music 100", 100, 0, 3, NULL);
1 row created. SQL> SQL> SQL> CREATE TABLE myLogTable (
2 code NUMBER, 3 message VARCHAR2(200), 4 info VARCHAR2(100) 5 );
Table created. SQL> SQL> SQL> SQL> DECLARE
2 myException EXCEPTION;
3 studentCount NUMBER(3);
4 studentMax NUMBER(3);
5
6 v_ErrorCode NUMBER;
7 v_ErrorText VARCHAR2(200);
8
9 BEGIN
10 SELECT current_lecturer, max_lecturer
11 INTO studentCount, studentMax
12 FROM session
13 WHERE department = "HIS" AND course = 101;
14 IF studentCount > studentMax THEN
15 RAISE myException;
16 END IF;
17 EXCEPTION
18 WHEN myException THEN
19 INSERT INTO myLogTable (info) VALUES ("History 101 has " || studentCount ||
20 "lecturer: max allowed is " || studentMax);
21 WHEN OTHERS THEN
22 v_ErrorCode := SQLCODE;
23 v_ErrorText := SUBSTR(SQLERRM, 1, 200); -- Note the use of SUBSTR here.
24 INSERT INTO myLogTable (code, message, info) VALUES
25 (v_ErrorCode, v_ErrorText, "Oracle error occurred");
26 END;
27 /
PL/SQL procedure successfully completed. SQL> SQL> drop table session; Table dropped. SQL> drop table myLogTable; Table dropped. SQL>
</source>
