:old and :new Pseudo-records
SQL>
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>
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>
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);
INSERT INTO lecturer (id, first_name, last_name, major, current_credits)
*
ERROR at line 1:
ORA-00001: unique constraint (JAVA2S.SYS_C004592) violated
SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
2 VALUES (10003, 'Jone', 'Bliss','Computer Science', 8);
INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
*
ERROR at line 1:
ORA-00001: unique constraint (JAVA2S.SYS_C004592) violated
SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
2 VALUES (10004, 'Man', 'Kyte','Economics', 8);
INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
*
ERROR at line 1:
ORA-00001: unique constraint (JAVA2S.SYS_C004592) violated
SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
2 VALUES (10005, 'Pat', 'Poll','History', 4);
INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
*
ERROR at line 1:
ORA-00001: unique constraint (JAVA2S.SYS_C004592) violated
SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
2 VALUES (10006, 'Tim', 'Viper','History', 4);
INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
*
ERROR at line 1:
ORA-00001: unique constraint (JAVA2S.SYS_C004592) violated
SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
2 VALUES (10007, 'Barbara', 'Blues','Economics', 7);
INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
*
ERROR at line 1:
ORA-00001: unique constraint (JAVA2S.SYS_C004592) violated
SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
2 VALUES (10008, 'David', 'Large','Music', 4);
INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
*
ERROR at line 1:
ORA-00001: unique constraint (JAVA2S.SYS_C004592) violated
SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
2 VALUES (10009, 'Chris', 'Elegant','Nutrition', 8);
INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
*
ERROR at line 1:
ORA-00001: unique constraint (JAVA2S.SYS_C004592) violated
SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
2 VALUES (10010, 'Rose', 'Bond','Music', 7);
INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
*
ERROR at line 1:
ORA-00001: unique constraint (JAVA2S.SYS_C004592) violated
SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
2 VALUES (10011, 'Rita', 'Johnson','Nutrition', 8);
INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
*
ERROR at line 1:
ORA-00001: unique constraint (JAVA2S.SYS_C004592) violated
SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
2 VALUES (10012, 'Sharon', 'Clear','Computer Science', 3);
INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
*
ERROR at line 1:
ORA-00001: unique constraint (JAVA2S.SYS_C004592) violated
SQL>
SQL> select * from lecturer;
ID FIRST_NAME LAST_NAME MAJOR CURRENT_CREDITS
---------- -------------------- -------------------- ------------------------------ ---------------
20001 Scott Lawson Computer Science 11
SQL>
SQL> drop table lecturer;
Table dropped.
SQL>
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