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How To Delete Duplicate Records in SQL Oracle
select rowid,empno,ename,job,mgr,hiredate,sal,comm,deptno from emp;
Using self-join with ROWID
=========================
delete FROM emp a
WHERE rowid NOT IN
(SELECT max(rowid) FROM emp b WHERE a.empno = b.empno );
(OR)
select rowid,empno,ename FROM emp a
WHERE rowid NOT IN
(SELECT min(rowid) FROM emp b WHERE a.empno = b.empno );
rollback;
Using rowid with GROUP BY Clause
================================
delete FROM emp
WHERE rowid not IN (SELECT min(rowid) FROM emp GROUP BY empno);
(OR)
select * FROM emp
WHERE rowid NOT IN (SELECT MAX(rowid) FROM emp GROUP BY empno);
rollback;
Using rowid with row_number()
===============================
select * FROM emp
WHERE rowid IN
(SELECT delrowid FROM
(SELECT rowid delrowid,row_number() over(partition BY empno order by empno) rownm
FROM emp )
WHERE rownm > 1 );
Using rowid with dense_rank()
=============================
delete FROM emp
WHERE rowid IN (SELECT delrowid
FROM
(SELECT rowid delrowid, dense_rank() over(partition BY empno order by rowid) rownm
FROM emp )
WHERE rownm > 1 );
rollback;
Using Group By
===============
select * FROM emp
WHERE (empno,ename,sal) IN
(SELECT empno,ename,sal FROM emp GROUP BY empno,ename,sal having count(empno)>1 );
rollback;
sub partitioning in oracle or composite partitioning in Oracle RANGE-LI...
******************************************************************************/
drop table EMP_COMP_RH;
CREATE TABLE EMP_COMP_RH
(
EMPNO NUMBER(4,0) ,
ENAME VARCHAR2(10 ),
JOB VARCHAR2(9 ),
MGR NUMBER(4,0),
HIREDATE DATE,
SAL NUMBER(7,2),
COMM NUMBER(7,2),
DEPTNO NUMBER(2,0)
)
PARTITION BY RANGE (HIREDATE)
SUBPARTITION BY HASH (EMPNO) SUBPARTITIONS 4
(Partition P1 values less than (TO_DATE ('01-JAN-1980','dd-MON-yyyy')),
Partition P2 values less than (TO_DATE ('01-JAN-1985','dd-MON-yyyy')),
Partition P3 values less than (TO_DATE ('01-JAN-1990','dd-MON-yyyy')),
Partition P4 values less than (TO_DATE ('01-JAN-2000','dd-MON-yyyy'))
)ENABLE ROW MOVEMENT;;
INSERT INTO EMP_COMP_RH select * from EMP;
commit;
BEGIN
DBMS_STATS.gather_table_stats('SDEV', 'EMP_COMP_RH');
END;
/
select * from EMP_COMP_RH;
drop table EMP_COMP_RL;
CREATE TABLE EMP_COMP_RL
(
EMPNO NUMBER(4,0) ,
ENAME VARCHAR2(10 ),
JOB VARCHAR2(9 ),
MGR NUMBER(4,0),
HIREDATE DATE,
SAL NUMBER(7,2),
COMM NUMBER(7,2),
DEPTNO NUMBER(2,0)
)
PARTITION BY RANGE (HIREDATE)
SUBPARTITION BY LIST(DEPTNO)
(Partition P1 values less than (TO_DATE ('01-JAN-1980','dd-MON-yyyy'))
(
SUBPARTITION SP1 VALUES ('10'),
SUBPARTITION SP2 VALUES ('20'),
SUBPARTITION SP3 VALUES ('30'),
SUBPARTITION SP4 VALUES ('40')
) ,
Partition P2 values less than (TO_DATE ('01-JAN-1985','dd-MON-yyyy'))
(
SUBPARTITION SP11 VALUES ('10'),
SUBPARTITION SP21 VALUES ('20'),
SUBPARTITION SP31 VALUES ('30'),
SUBPARTITION SP41 VALUES ('40')
),
Partition P3 values less than (TO_DATE ('01-JAN-1990','dd-MON-yyyy'))
(
SUBPARTITION SP12 VALUES ('10'),
SUBPARTITION SP22 VALUES ('20'),
SUBPARTITION SP32 VALUES ('30'),
SUBPARTITION SP42 VALUES ('40')
),
Partition P4 values less than (TO_DATE ('01-JAN-2000','dd-MON-yyyy'))
(
SUBPARTITION SP13 VALUES ('10'),
SUBPARTITION SP23 VALUES ('20'),
SUBPARTITION SP33 VALUES ('30'),
SUBPARTITION SP43 VALUES ('40')
)
)ENABLE ROW MOVEMENT;
INSERT INTO EMP_COMP_RL select * from EMP;
commit;
select * from EMP_COMP_RL;
BEGIN
DBMS_STATS.gather_table_stats('SDEV', 'EMP_COMP_RL');
END;
/
What is a Hash Partition in Oracle
/* =========================================================================*/
DROP TABLE EMP_HASH;
CREATE TABLE EMP_HASH
(
EMPNO NUMBER(4,0) ,
ENAME VARCHAR2(10 ),
JOB VARCHAR2(9 ),
MGR NUMBER(4,0),
HIREDATE DATE,
SAL NUMBER(7,2),
COMM NUMBER(7,2),
DEPTNO NUMBER(2,0)
)
PARTITION BY HASH ( EMPNO )
PARTITIONS 4
ENABLE ROW MOVEMENT;
insert into EMP_HASH select * from EMP;
commit;
BEGIN
DBMS_STATS.gather_table_stats('SDEV', 'EMP_HASH');
END;
/
select * from EMP_HASH where empno=7369;
What is a LIST Partition in Oracle
/* ==========================================================================*/
DROP TABLE EMP_LIST;
CREATE TABLE EMP_LIST
(
EMPNO NUMBER(4,0) ,
ENAME VARCHAR2(10 ),
JOB VARCHAR2(9 ),
MGR NUMBER(4,0),
HIREDATE DATE,
SAL NUMBER(7,2),
COMM NUMBER(7,2),
DEPTNO NUMBER(2,0)
)
PARTITION BY LIST (DEPTNO)
(
PARTITION P1 VALUES ('10'),
PARTITION P2 VALUES ('20'),
PARTITION P3 VALUES ('30'),
PARTITION P4 VALUES ('40')
) ENABLE ROW MOVEMENT;
INSERT INTO EMP_LIST SELECT * FROM EMP;
COMMIT;
BEGIN
DBMS_STATS.gather_table_stats('SDEV', 'EMP_LIST');
END;
/
select * from EMP_LIST where deptno=20;
select * from emp where deptno=10;
What is a Partition in Oracle and Type of Partitions , Range Partition
/*****************************************************************************
ORACLE PARTITIONS AND TYPES.
1) Range Partitioning
2) LIST Partitioning
3) HASH Partitioning
4) Composite RANGE-HASH Partitioning
5) Composite RANGE-LIST Partitioning
******************************************************************************/
drop table emp_part;
CREATE TABLE emp_part
(
EMPNO NUMBER(4,0) ,
ENAME VARCHAR2(10 ),
JOB VARCHAR2(9 ),
MGR NUMBER(4,0),
HIREDATE DATE,
SAL NUMBER(7,2),
COMM NUMBER(7,2),
DEPTNO NUMBER(2,0)
)PARTITION BY RANGE (sal)
INTERVAL (1000)
(
PARTITION p1 VALUES LESS THAN (1000) ,
PARTITION p2 VALUES LESS THAN (2000) ,
PARTITION p3 VALUES LESS THAN (3000) ,
PARTITION p4 VALUES LESS THAN (4000)
)ENABLE ROW MOVEMENT ;
select * from emp_part PARTITION(P2); --where sal>4000;
;
BEGIN
DBMS_STATS.gather_table_stats('SDEV', 'EMP_PART');
END;
/
insert into emp_part select * from emp;
commit;
select * from emp_part PARTITION(p3);
drop table emp_RANGE_DT;
CREATE TABLE emp_RANGE_DT
(
EMPNO NUMBER(4,0) ,
ENAME VARCHAR2(10 ),
JOB VARCHAR2(9 ),
MGR NUMBER(4,0),
HIREDATE DATE,
SAL NUMBER(7,2),
COMM NUMBER(7,2),
DEPTNO NUMBER(2,0)
)
PARTITION BY RANGE (HIREDATE)
(Partition P1 values less than (TO_DATE ('01-JAN-1980','dd-MON-yyyy')),
Partition P2 values less than (TO_DATE ('01-JAN-1985','dd-MON-yyyy')),
Partition P3 values less than (TO_DATE ('01-JAN-1990','dd-MON-yyyy')),
Partition P4 values less than (TO_DATE ('01-JAN-2000','dd-MON-yyyy'))
) ENABLE ROW MOVEMENT;;
insert into emp_RANGE_DT select * from emp;
commit;
BEGIN
DBMS_STATS.gather_table_stats('SDEV', 'EMP_RANGE_DT');
END;
/
/* ==========================================================================*/
DROP TABLE EMP_LIST;
CREATE TABLE EMP_LIST
(
EMPNO NUMBER(4,0) ,
ENAME VARCHAR2(10 ),
JOB VARCHAR2(9 ),
MGR NUMBER(4,0),
HIREDATE DATE,
SAL NUMBER(7,2),
COMM NUMBER(7,2),
DEPTNO NUMBER(2,0)
)
PARTITION BY LIST (DEPTNO)
(
PARTITION P1 VALUES ('10'),
PARTITION P2 VALUES ('20'),
PARTITION P3 VALUES ('30'),
PARTITION P4 VALUES ('40')
) ENABLE ROW MOVEMENT;
INSERT INTO EMP_LIST SELECT * FROM EMP;
COMMIT;
BEGIN
DBMS_STATS.gather_table_stats('SDEV', 'EMP_LIST');
END;
/
select * from EMP_LIST where deptno=20;
select * from emp where deptno=10;
What is Global temporary Tables in Oracle
/*****************************************************************************
DECLARE GLOBAL TEMPORARY TABLE table-Name
{ column-definition [ , column-definition ] * }
[ ON COMMIT {DELETE | PRESERVE} ROWS ]
NOT LOGGED [ON ROLLBACK DELETE ROWS]
*****************************************************************************/
CREATE GLOBAL TEMPORARY TABLE students
( student_id numeric(10) NOT NULL,
student_name varchar2(50) NOT NULL,
student_address varchar2(50)
);
drop table GLOBAL_TEMP_TABLE ;
CREATE GLOBAL TEMPORARY TABLE GLOBAL_TEMP_TABLE
( id NUMBER,
description VARCHAR2(20)
) ON COMMIT DELETE ROWS;
insert into GLOBAL_TEMP_TABLE values(1,'this is first row');
select * from GLOBAL_TEMP_TABLE;
commit;
drop table GLOBAL_TEMP PURGE;
CREATE GLOBAL TEMPORARY TABLE GLOBAL_TEMP
(
id NUMBER,
description VARCHAR2(50)
)ON COMMIT PRESERVE ROWS;
commit;
insert into global_temp values(2,'this is ON COMMIT PRESERVE ROWS');
select * from global_temp;
Introduction To PLSQL Triggers and Types of Triggers
/*****************************************************************************
Oracle PLSQL TRIGGERS..
TYPES OF TRIGGERS
-----------------
1) DML Triggers
2) DDL Triggers
3) SYSTEM Triggers (STARTUP, SHUTDOWN) and user Evens (LOGON & LOGOFF)
4) INSTEAD OF Trigger
TYPES OF DML Triggers:
----------------------
ROW LEVEL & STATEMENT LEVEL TRIGGERS
=====================================
Firing Point : BEFORE
=========================
1) BEFORE INSERT TRIGGER
2) BEFORE UPDATE TRIGGER
3) BEFORE DELETE TRIGGER
Firing Point : AFTER
=====================
1) AFTER INSERT TRIGGER
2) AFTER UPDATE TRIGGER
3) AFTER DELETE TRIGGER
OLD & NEW Qualifiers.
-----------------------
INSERT : NEW
UPDATE : OLD & NEW
DELETE : OLD
Conditional Predicates
--------------------------
INSERTING
UPDATING
DELETING
*******************************************************************************/
CREATE [OR REPLACE] TRIGGER trigger_name
BEFORE | AFTER
[INSERT, UPDATE, DELETE [COLUMN NAME..]
ON table_name
Referencing [ OLD AS OLD | NEW AS NEW ]
FOR EACH ROW | FOR EACH STATEMENT [ WHEN Condition ]
DECLARE
[declaration_section
variable declarations;
constant declarations;
]
BEGIN
[executable_section
PL/SQL execute/subprogram body
]
EXCEPTION
[exception_section
PL/SQL Exception block
]
END;
********************************************************************************
/
CREATE or REPLACE TRIGGER EMP_TRIGGER
BEFORE
INSERT ON emp
FOR EACH ROW
BEGIN
:new.ename := upper(:new.ename);
END;
CREATE or REPLACE TRIGGER EMP_DELETE_TRIGGER
AFTER
DELETE ON emp
FOR EACH ROW
BEGIN
IF :old.empno = 7782 THEN
null;
raise_application_error(-20015, 'You cant delete this row');
END IF;
END;
delete from emp where empno=7782;
select * from mytable;
select * from emp;
CREATE or REPLACE TRIGGER EMP_DELETE_TRG_1
BEFORE
DELETE ON emp
FOR EACH ROW
BEGIN
insert into mytable values(:old.empno,sysdate);
END;
What is Conditional Predicates and Qualifiers in TRIGGERS PLSQL
CREATE OR REPLACE TRIGGER EMP_TRIGGER_PREDICATES
BEFORE INSERT OR DELETE OR UPDATE ON emp
FOR EACH ROW
DECLARE
v_ChangeType CHAR(1);
BEGIN
/* Use 'I' for an INSERT, 'D' for DELETE, and 'U' for UPDATE. */
IF INSERTING THEN
v_ChangeType := 'I';
ELSIF UPDATING THEN
v_ChangeType := 'U';
ELSE
v_ChangeType := 'D';
END IF;
DBMS_OUTPUT.put_line(v_ChangeType ||'- '|| USER ||'-' ||SYSDATE);
END EMP_TRIGGER_PREDICATES;
/
PLSQL DML Triggers and Types of DML Triggers
/*****************************************************************************
Oracle PLSQL TRIGGERS..
TYPES OF TRIGGERS
-----------------
1) DML Triggers
2) DDL Triggers
3) SYSTEM Triggers (STARTUP, SHUTDOWN) and user Evens (LOGON & LOGOFF)
4) INSTEAD OF Trigger
TYPES OF DML Triggers:
----------------------
ROW LEVEL & STATEMENT LEVEL TRIGGERS
=====================================
Firing Point : BEFORE
=========================
1) BEFORE INSERT TRIGGER
2) BEFORE UPDATE TRIGGER
3) BEFORE DELETE TRIGGER
Firing Point : AFTER
=====================
1) AFTER INSERT TRIGGER
2) AFTER UPDATE TRIGGER
3) AFTER DELETE TRIGGER
OLD & NEW Qualifiers.
-----------------------
INSERT : NEW
UPDATE : OLD & NEW
DELETE : OLD
Conditional Predicates
--------------------------
INSERTING
UPDATING
DELETING
*******************************************************************************/
CREATE [OR REPLACE] TRIGGER trigger_name
BEFORE | AFTER
[INSERT, UPDATE, DELETE [COLUMN NAME..]
ON table_name
Referencing [ OLD AS OLD | NEW AS NEW ]
FOR EACH ROW | FOR EACH STATEMENT [ WHEN Condition ]
DECLARE
[declaration_section
variable declarations;
constant declarations;
]
BEGIN
[executable_section
PL/SQL execute/subprogram body
]
EXCEPTION
[exception_section
PL/SQL Exception block
]
END;
********************************************************************************
/
CREATE or REPLACE TRIGGER EMP_TRIGGER
BEFORE
INSERT ON emp
FOR EACH ROW
BEGIN
:new.ename := upper(:new.ename);
END;
CREATE or REPLACE TRIGGER EMP_DELETE_TRIGGER
AFTER
DELETE ON emp
FOR EACH ROW
BEGIN
IF :old.empno = 7782 THEN
null;
raise_application_error(-20015, 'You cant delete this row');
END IF;
END;
What is Instead of Trigger in PLSQL
/*****************************************************************************
INSTEAD OF TRIGGER -- To Update Complex Views...
******************************************************************************/
drop table employee;
CREATE TABLE employee
(
employee_id number(10) primary key,
employee_name varchar2(20),
location varchar2(20),
department_id number references departments(department_id)
);
DROP TABLE departments;
CREATE TABLE departments
(
department_id number(10) primary key,
department_name varchar2(30),
creation_date date default sysdate
);
CREATE OR REPLACE VIEW EMPLOYEE_DEPART_V AS
SELECT dept.department_id, dept.department_name,dept.creation_Date,
emp.employee_id,
emp.employee_name, emp.location
FROM DEPARTMENTS dept, EMPLOYEE emp
WHERE dept.department_id = emp.department_id;
insert into EMPLOYEE_DEPART_V values(1,'IT',SYSDATE,1,'RAVEENDRA','BANGALORE');
insert into EMPLOYEE_DEPART_V values(2,'SALES',SYSDATE,2,'RESHWANTH','HYDERABAD');
insert into EMPLOYEE_DEPART_V values(2,'IT',SYSDATE,2,'RAVEENDRA','BANGALORE');
commit;
delete from departments;
select * from EMPLOYEE_DEPART_V;
select * from employee;
select * from departments;
DROP TRIGGER EMP_DEPT_Instead_OF_TRG;
CREATE OR REPLACE TRIGGER EMP_DEPT_Instead_OF_TRG
INSTEAD OF INSERT ON EMPLOYEE_DEPART_V
DECLARE
duplicate_info EXCEPTION;
PRAGMA EXCEPTION_INIT (duplicate_info, -00001);
BEGIN
INSERT INTO departments (department_id, department_name, creation_date)
VALUES (
:new.department_id,
:new.department_name,
:new.creation_date);
INSERT INTO employee
(employee_id,employee_name,location,DEPARTMENT_ID)
VALUES (:new.employee_id, :new.employee_name, :new.location,:new.DEPARTMENT_ID);
EXCEPTION
WHEN duplicate_info THEN
RAISE_APPLICATION_ERROR (
num=> -20107,
msg=> 'Duplicate employee or department id');
END EMP_DEPT_Instead_OF_TRG;
PLSQL DDL Triggers with examples
/*****************************************************************************
DDL Triggers Examples..
CREATE OR REPLACE TRIGGER DDLTrigger_name
AFTER DDL/LOGON/LOGOFF ON DATABASE/SCHEMA
BEGIN
-----
END;
******************************************************************************/
CREATE TABLE DDL_TABLE_LOG
(
ora_dict_obj_name VARCHAR2(100),
ora_login_user VARCHAR2(100),
creation_date DATE,
ora_sysevent VARCHAR2(100),
ora_dict_obj_type VARCHAR2(100),
ora_dict_obj_owner VARCHAR2(100)
);
/
CREATE OR REPLACE TRIGGER MY_DDL_TRIGGER AFTER DDL ON DATABASE
BEGIN
INSERT
INTO DDL_TABLE_LOG VALUES
(
ora_dict_obj_name ,
ora_login_user ,
sysdate ,
ora_sysevent ,
ora_dict_obj_type ,
ora_dict_obj_owner
);
END;
/
select * from DDL_TABLE_LOG;
truncate table DDL_TABLE_LOG;
LOGON & LOGOFF Triggers in PLSQL
/*****************************************************************************
USER EVENT LOGON & LOGOFF Triggers Examples..
CREATE OR REPLACE TRIGGER DDLTrigger_name
AFTER LOGON/LOGOFF ON DATABASE/SCHEMA
BEGIN
-----
END;
******************************************************************************/
DROP TABLE USER_EVENT_LOG;
CREATE TABLE USER_EVENT_LOG
(
ora_login_user VARCHAR2(100),
creation_date DATE,
ora_sysevent VARCHAR2(100)
);
/
CREATE OR REPLACE TRIGGER MY_DDL_TRIGGER_LOGON AFTER LOGON ON DATABASE
BEGIN
INSERT
INTO USER_EVENT_LOG VALUES
(
ora_login_user ,
sysdate ,
ora_sysevent
);
END;
/
CREATE OR REPLACE TRIGGER MY_DDL_TRIGGER_LOGOFF BEFORE LOGOFF ON DATABASE
BEGIN
INSERT
INTO USER_EVENT_LOG VALUES
(
ora_login_user ,
sysdate ,
ora_sysevent
);
END;
/
What is PRAGMA AUTONOMOUS TRANSACTION in PLSQL?
/*****************************************************************************
PRAGMA AUTONOMOUS_TRANSACTION
*****************************************************************************/
The Child Code runs independently of its parent
the Child code can commit or rollback and parent resumes
the parent code can continue without affecting child work
drop table my_test;
CREATE TABLE my_test (
id NUMBER NOT NULL,
description VARCHAR2(50) NOT NULL
);
INSERT INTO my_test (id, description) VALUES (1, 'Description for 1');
INSERT INTO my_test (id, description) VALUES (2, 'Description for 2');
DECLARE
PRAGMA AUTONOMOUS_TRANSACTION;
BEGIN
FOR i IN 3 .. 10 LOOP
INSERT INTO my_test (id, description)
VALUES (i, 'Description for ' || i);
END LOOP;
commit;
END;
/
select * from my_test;
rollback;
delete from my_test;
CREATE or REPLACE TRIGGER EMP_TRIGGER
BEFORE
INSERT ON emp
FOR EACH ROW
DECLARE
PRAGMA AUTONOMOUS_TRANSACTION;
BEGIN
:new.ename := upper(:new.ename);
commit;
END;
/
insert into emp select * from scott.emp;
commit;
What is Mutating Table Error in Triggers
/*****************************************************************************
WHAT IS MUTATING TABLE ERROR???????????????????????????????????????????
*****************************************************************************/
CREATE TABLE mutate_tables1 ( num NUMBER );
CREATE TABLE mutate_tables2 ( id NUMBER );
INSERT INTO mutate_tables2 VALUES (NULL);
COMMIT;
CREATE OR REPLACE TRIGGER mutate_Trigger1
AFTER INSERT ON mutate_tables2
FOR EACH ROW
DECLARE
PRAGMA AUTONOMOUS_TRANSACTION;
BEGIN
UPDATE mutate_tables1
SET num = ( SELECT MAX(id) FROM mutate_tables2 );
COMMIT;
END;
/
INSERT INTO mutate_tables2 VALUES (1);
commit;
select * from mutate_tables2;
select * from mutate_tables1;
BULK COLLECT and BULK BIND in PLSQL
/*****************************************************************************
BULK COLLECT & FORALL (BULK BINDING)......
******************************************************************************/
SET SERVEROUTPUT ON;
create table bulk_table(no number);
create table bulk_bind(no number);
----------------------------
BEGIN
FOR i IN 1..1000000
LOOP
INSERT INTO bulk_table VALUES (i);
END LOOP;
COMMIT;
END;
/
select count(*) from bulk_table;
------------------------
DECLARE
TYPE rt IS TABLE OF bulk_table%rowtype;
vt rt;
BEGIN
SELECT * BULK COLLECT INTO vt FROM bulk_table;
FORALL i IN 1..vt.count
INSERT INTO bulk_bind VALUES vt(i);
COMMIT;
END;
/
----------------------------------
select count(*) from bulk_bind;
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