Oracle PL/SQL Tutorial/Trigger/NEW OLD
Содержание
- 1 :old and :new Pseudo-records, Example 1
- 2 :old and :new Pseudo-records, Example 2
- 3 Old and new value
- 4 Output new and old value in a before update trigger
- 5 Raise application error in a trigger in case of invalid new value
- 6 Reference new value with :NEW in a before insert or update trigger
- 7 REFERENCING OLD AS old NEW AS new
- 8 REFERENCING OLD AS old_values NEW AS new_values
- 9 Refernece an old value in :OLD after update trigger
:old and :new Pseudo-records, Example 1
<source lang="sql">
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> 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> CREATE OR REPLACE TRIGGER TempDelete
2 BEFORE DELETE ON employee 3 FOR EACH ROW 4 DECLARE 5 v_TempRec employee%ROWTYPE; 6 BEGIN 7 /* This is not a legal assignment, since :old is not truly 8 a record. */ 9 --v_TempRec := :old; 10 11 /* We can accomplish the same thing, however, by assigning 12 the fields individually. */ 13 v_TempRec.first_name := :old.first_name; 14 v_TempRec.last_name := :old.last_name; 15 16 DBMS_OUTPUT.put_line(v_TempRec.first_name); 17 DBMS_OUTPUT.put_line(v_TempRec.last_name); 18 END TempDelete; 19 /
Trigger created. SQL> SQL> delete from employee; Jason Martin Alison Mathews James Smith Celia Rice Robert Black Linda Green David Larry James Cat 8 rows deleted. SQL> SQL> SQL> SQL> -- clean the table SQL> drop table Employee
2 /
Table dropped.</source>
:old and :new Pseudo-records, Example 2
<source lang="sql">
SQL> SQL> create sequence seq; Sequence created. 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> 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 3 rows selected. SQL> SQL> SQL> SQL> CREATE OR REPLACE TRIGGER GenerateEmployeeID
2 BEFORE INSERT OR UPDATE ON employee 3 FOR EACH ROW 4 BEGIN 5 /* Fill in the ID field of employees with the next value from 6 the sequence.*/ 7 SELECT seq.nextval 8 INTO :new.ID 9 FROM dual; 10 END GenerateEmployeeID; 11 /
Trigger created. SQL> 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> 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 1 Celia Rice 24-OCT-82 21-APR-99 2344.78 Vancouver Manager 2 Robert Black 15-JAN-84 08-AUG-98 2334.78 Vancouver Tester 3 Linda Green 30-JUL-87 04-JAN-96 4322.78 New York Tester 4 David Larry 31-DEC-90 12-FEB-98 7897.78 New York Manager 5 James Cat 17-SEP-96 15-APR-02 1232.78 Vancouver Tester 8 rows selected. SQL> SQL> drop sequence seq; Sequence dropped. SQL> SQL> SQL> SQL> SQL> -- clean the table SQL> drop table Employee
2 /
Table dropped. SQL></source>
Old and new value
<source lang="sql">
SQL> SQL> CREATE TABLE game_player
2 (player_id NUMBER, 3 game_id NUMBER, 4 group_number NUMBER, 5 marked VARCHAR2(1) DEFAULT "N", 6 pcmac VARCHAR2(1) DEFAULT "N", 7 score NUMBER, 8 CONSTRAINT game_player_pk 9 PRIMARY KEY (player_id, game_id, group_number));
Table created. SQL> SQL> SQL> CREATE OR REPLACE TRIGGER before_insert_row
2 BEFORE INSERT
3 ON game_player
4 FOR EACH ROW
5 BEGIN
6 DBMS_OUTPUT.put_line ("Before Insert Row");
7 DBMS_OUTPUT.put_line ("Old ID " || :OLD.player_id);
8 DBMS_OUTPUT.put_line ("New ID " || :NEW.player_id);
9 DBMS_OUTPUT.put_line ("Old ROWID " || ROWIDTOCHAR (:OLD.ROWID));
10 DBMS_OUTPUT.put_line ("New ROWID " || ROWIDTOCHAR (:NEW.ROWID));
11 END;
12 /
Trigger created. SQL> SQL> BEGIN
2 INSERT INTO game_player(player_id, game_id, group_number, marked, pcmac, score) 3 VALUES (1, 1, 1, "Y", "N", NULL); 4 5 UPDATE game_player 6 SET player_id = player_id; 7 8 DELETE game_player; 9 END; 10 11 /
PL/SQL procedure successfully completed. SQL> SQL> drop table game_player; Table dropped.</source>
Output new and old value in a before update trigger
<source lang="sql">
SQL> SQL> create table t ( x int, y int ); Table created. SQL> SQL> insert into t values ( 1, 1 ); 1 row created. SQL> SQL> create or replace trigger t_bufer
2 before update on t for each row 3 begin 4 dbms_output.put_line( "old.x = " || :old.x ||", old.y = " || :old.y ); 5 dbms_output.put_line( "new.x = " || :new.x ||", new.y = " || :new.y ); 6 end; 7 /
Trigger created. SQL> set serveroutput on SQL> update t set x = x+1; old.x = 1, old.y = 1 new.x = 2, new.y = 1 1 row updated. SQL> SQL> drop table t; Table dropped. SQL></source>
Raise application error in a trigger in case of invalid new value
<source lang="sql">
SQL> SQL> create table t ( x int ); Table created. SQL> SQL> create trigger t_trigger before insert on t for each row
2 begin 3 for x in ( select * 4 from dual 5 where :new.x > 10) 6 loop 7 raise_application_error( -20001, "check failed" ); 8 end loop; 9 end; 10 /
Trigger created. SQL> show errors No errors. SQL> SQL> insert into t select 1 from all_users; 15 rows created. SQL> SQL> set autotrace traceonly statistics SQL> SQL> insert into t select 1 from all_users; 15 rows created.
Statistics
16 recursive calls
15 db block gets
73 consistent gets
0 physical reads
0 redo size
924 bytes sent via SQL*Net to client
947 bytes received via SQL*Net from client
6 SQL*Net roundtrips to/from client
1 sorts (memory)
0 sorts (disk)
15 rows processed
SQL> SQL> set autotrace off SQL> SQL> drop table t; Table dropped. SQL> SQL> SQL></source>
Reference new value with :NEW in a before insert or update trigger
<source lang="sql">
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 OR REPLACE TRIGGER employee_insert_update
2 BEFORE INSERT OR UPDATE ON employee 3 FOR EACH ROW 4 DECLARE 5 dup_flag INTEGER; 6 BEGIN 7 --Force all employee names to uppercase. 8 :NEW.first_name := UPPER(:NEW.first_name); 9 END; 10 /
Trigger 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> -- clean the table SQL> drop table Employee
2 /
Table dropped. SQL></source>
REFERENCING OLD AS old NEW AS new
<source lang="sql">
SQL> SQL> CREATE TABLE game_player
2 (player_id NUMBER, 3 game_id NUMBER, 4 group_number NUMBER, 5 marked VARCHAR2(1) DEFAULT "N", 6 pcmac VARCHAR2(1) DEFAULT "N", 7 score NUMBER, 8 CONSTRAINT game_player_pk 9 PRIMARY KEY (player_id, game_id, group_number));
Table created. SQL> SQL> SQL> -- explicit default old and new SQL> CREATE OR REPLACE TRIGGER old_new_update
2 BEFORE update ON game_player
3 REFERENCING OLD AS old NEW AS new
4 FOR EACH ROW
5 BEGIN
6 DBMS_OUTPUT.PUT_LINE("Old marked = " || :old.marked);
7 DBMS_OUTPUT.PUT_LINE("New marked = " || :new.marked);
8 END;
9 /
Trigger created. SQL> SQL> SQL> SQL> drop table game_player; Table dropped.</source>
REFERENCING OLD AS old_values NEW AS new_values
<source lang="sql">
SQL> CREATE TABLE game_player
2 (player_id NUMBER, 3 game_id NUMBER, 4 group_number NUMBER, 5 marked VARCHAR2(1) DEFAULT "N", 6 pcmac VARCHAR2(1) DEFAULT "N", 7 score NUMBER, 8 CONSTRAINT game_player_pk 9 PRIMARY KEY (player_id, game_id, group_number));
Table created. SQL> SQL> SQL> -- changing the defaults SQL> CREATE OR REPLACE TRIGGER old_new_delete
2 BEFORE delete ON game_player
3 REFERENCING OLD AS old_values NEW AS new_values
4 FOR EACH ROW
5 BEGIN
6 DBMS_OUTPUT.PUT_LINE("Old marked = " || :old_values.marked);
7 DBMS_OUTPUT.PUT_LINE("New marked = " || :new_values.marked);
8 END;
9 /
Trigger created. SQL> SQL> SQL> SQL> drop table game_player; Table dropped.</source>
Refernece an old value in :OLD after update trigger
<source lang="sql">
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> 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> CREATE OR REPLACE TRIGGER employee_upd
2 AFTER UPDATE OF id ON employee
3 FOR EACH ROW
4 BEGIN
5 DBMS_OUTPUT.PUT_LINE (":OLD.id" || :OLD.id);
6 END;
7 /
Trigger created. SQL> SQL> update employee set id = "1";
- OLD.id01
- OLD.id02
- OLD.id03
- OLD.id04
- OLD.id05
- OLD.id06
- OLD.id07
- OLD.id08
8 rows updated. SQL> SQL> -- clean the table SQL> drop table Employee
2 /
Table dropped.</source>
