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SQL>
SQL> set echo on
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> 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);
1 row created.
SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
2 VALUES (10003, 'Jone', 'Bliss','Computer Science', 8);
1 row created.
SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
2 VALUES (10004, 'Man', 'Kyte','Economics', 8);
1 row created.
SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
2 VALUES (10005, 'Pat', 'Poll','History', 4);
1 row created.
SQL>
SQL> INSERT INTO lecturer (id, first_name, last_name, major,current_credits)
2 VALUES (10006, 'Tim', 'Viper','History', 4);
1 row created.
SQL>
SQL>
SQL> ALTER SESSION SET SQL_TRACE = TRUE;
Session altered.
SQL>
SQL> CREATE OR REPLACE FUNCTION lecturerStatus(
2 p_NumCredits IN NUMBER)
3 RETURN VARCHAR2 AS
4 BEGIN
5 IF p_NumCredits = 0 THEN
6 RETURN 'Inactive';
7 ELSIF p_NumCredits <= 12 THEN
8 RETURN 'Part Time';
9 ELSE
10 RETURN 'Full Time';
11 END IF;
12 END lecturerStatus;
13 /
Function created.
SQL>
SQL> SELECT id
2 FROM lecturer
3 WHERE SUBSTR(lecturerStatus(current_credits), 1, 20) =
4 'Part Time';
ID
----------
10001
10002
10003
10004
10005
10006
6 rows selected.
SQL>
SQL> CREATE OR REPLACE FUNCTION lecturerStatus(p_NumCredits IN NUMBER)
2 RETURN VARCHAR2
3 DETERMINISTIC AS
4 BEGIN
5 IF p_NumCredits = 0 THEN
6 RETURN 'Inactive';
7 ELSIF p_NumCredits <= 12 THEN
8 RETURN 'Part Time';
9 ELSE
10 RETURN 'Full Time';
11 END IF;
12 END lecturerStatus;
13 /
Function created.
SQL>
SQL> CREATE INDEX lecturer_index ON lecturer
2 (SUBSTR(lecturerStatus(current_credits), 1, 20))
3 COMPUTE STATISTICS;
Index created.
SQL>
SQL> ALTER SESSION SET QUERY_REWRITE_ENABLED = TRUE;
Session altered.
SQL> ALTER SESSION SET QUERY_REWRITE_INTEGRITY = TRUSTED;
Session altered.
SQL>
SQL> SELECT /*+ index(lecturer,lecturer_index) */ id
2 FROM lecturer
3 WHERE SUBSTR(lecturerStatus(current_credits), 1, 20) =
4 'Part Time';
ID
----------
10001
10002
10003
10004
10005
10006
6 rows selected.
SQL>
SQL> DROP INDEX lecturer_index;
Index dropped.
SQL>
SQL> drop table lecturer;
Table dropped.
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