ALTER SESSION SET QUERY_REWRITE_ENABLED

    
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.

Related examples in the same category

1.	alter the session with the ALTER SESSION statement and set the session's time zone forward
2.	alter session set nls_date_format = 'dd-MON-yyyy hh24:mi:ss';
3.	alter session set OPTIMIZER_MODE = RULE
4.	Adjust your session time zone to -08:00, display the contents of your time table.
5.	alter session set cursor_sharing = force
6.	alter session set use_stored_outlines
7.	Event-based call and exception tracing
8.	event-based call and exception tracing.
9.	SQL trace
10.	uses dynamic SQL to issue an ALTER SESSION statement.
11.	alter session set sql_trace=true
12.	sql_trace a stored procedure
13.	Set the following session parameters to enable query rewrite:
14.	If your session time zone is not US/Central (-06:00), alter your session to Central time:
15.	alter session set nls_date_format = 'DD-MON-YYYY HH24:MI:SS'
16.	Alter time_zone
17.	sessiontimezone, current_timestamp
18.	demonstrates the use of DBMS_SQL to execute an ALTER SESSION statement.
19.	interaction between ALTER SESSION and autonomous transactions.
20.	ALTER SESSION SET SQL_TRACE = TRUE
21.	ALTER SESSION SET optimizer_dynamic_sampling
22.	alter session set NLS_DATE_FORMAT='DD-MM-YYYY'
23.	alter session set current_schema=Smart
24.	alter session set db_file_multiblock_read_count
25.	alter session set hash_area_size
26.	alter session set nls_date_format='dd-mm-yyyy', nls_language=Dutch, nls_currency='Eur'
27.	alter session set optimizer_index_cost_adj, alter session set optimizer_index_caching
28.	alter session set optimizer_max_permutations=80000
29.	alter session set optimizer_mode=all_rows
30.	alter session set optimizer_mode=first_rows
31.	alter session set query_rewrite_integrity=enforced
32.	alter session set sort_area_size = 102400000
33.	alter session set workarea_size_policy=manual
34.	alter system flush shared_pool
35.	alter system quiesce restricted
36.	alter system resume
37.	alter system suspend
38.	set optimizer_features_enable = '8.1.5' scope = spfile
39.	show filestat
40.	show parameter optimizer_features
41.	show verify
42.	If your session time zone is not US/Central Standard Time (-06:00), alter your session to Central Standard time:

ALTER SESSION SET QUERY_REWRITE_ENABLED : Session variable « SQL Plus « Oracle PL / SQL

Related examples in the same category