How to partition a non-partitioned table

You can partition a non-partitioned table three different ways:

A. Export/Import method
B. Partition exchange method
C. Insert with a sub-query method

Any of these 3 methods will create a partitioned table from

an existing non-partitioned table. Here we are considering that EMP is a non-partitioned table.

A. Export/import method

1) Export non-partitioned EMP table:
exp username/password tables=emp file=emp_exp.dmp log=emp_exp.log

2) Drop the table:
drop table emp;

3) Recreate EMP table with partitions:
create table EMP (empo number(3), name varchar2(15)) partition by range (qty) (partition p1 values less than (501), partition p2 values less than (maxvalue));

4) Import the table with ignore=y:
imp usr/pswd file=exp.dmp ignore=y The ignore=y causes the import to skip the table creation and continues to load all rows.

B. Insert with a subquery method

1) Create a partitioned table:
create table EMP_PART (empo number(3), name varchar2(15)) partition by range (qty) (partition p1 values less than (501), partition p2 values less than (maxvalue));

2) Insert into the partitioned table with a subquery from the non-partitioned table:
insert into EMP_PRAT (qty, name) select * from EMP Note: EMP is a non-partition table.

3) If you want the partitioned table to have the same name as the original table, then drop the original table and rename the new table:
drop table EMP; alter table EMP_PART rename to EMP;

C. Partition Exchange method
ALTER TABLE EXCHANGE PARTITION can be used to convert a partition (or subpartition) into a non-partitioned table and a non-partitioned table into a partition (or subpartition) of a partitioned table by exchanging their data and index segments.

1) Create table dummy_t as select with the required partitions
2) Alter table EXCHANGE partition with ;

Example
-------
SQL> CREATE TABLE p_emp 2 (sal NUMBER(7,2)) 3 PARTITION BY RANGE(sal) 4 (partition emp_p1 VALUES LESS THAN (2000), 5 partition emp_p2 VALUES LESS THAN (4000));
Table created.

SQL> SELECT * FROM emp;
EMPNO ENAME JOB MGR HIREDATE SAL --------- ---------- --------- --------- --------- --------- 7369 SMITH CLERK 7902 17-DEC-80 800 7499 ALLEN SALESMAN 7698 20-FEB-81 1600 7521 WARD SALESMAN 7698 22-FEB-81 1250 7566 JONES MANAGER 7839 02-APR-81 2975 7654 MARTIN SALESMAN 7698 28-SEP-81 1250 7698 BLAKE MANAGER 7839 01-MAY-81 2850 7782 CLARK MANAGER 7839 09-JUN-81 2450 7788 SCOTT ANALYST 7566 19-APR-87 3000 7839 KING PRESIDENT 17-NOV-81 5000 7844 TURNER SALESMAN 7698 08-SEP-81 1500 7876 ADAMS CLERK 7788 23-MAY-87 1100 7900 JAMES CLERK 7698 03-DEC-81 950 7902 FORD ANALYST 7566 03-DEC-81 3000 7934 MILLER CLERK 7782 23-JAN-82 1300
14 rows selected.

SQL> CREATE TABLE dummy_y as SELECT sal FROM emp WHERE sal<2000;> CREATE TABLE dummy_z as SELECT sal FROM emp WHERE sal BETWEEN 2000 AND 3999;
Table created.

SQL> alter table p_emp exchange partition emp_p1 with table dummy_y;
Table altered.

SQL> alter table p_emp exchange partition emp_p2 with table dummy_z;
Table altered