Existing table to be converted into Oracle Partition!Possible!
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Thread: Existing table to be converted into Oracle Partition!Possible!

  1. #1
    Join Date
    Feb 2001
    Posts
    286
    Hi!

    Working on Oracle v8i with OS as Win2000/NT!

    Is it possible for the existing Table with datas loaded to get converted into Oracle partition.Any possibility through ALTER TABLE TABLENAME PARTITION PARTITION NAME TABLESPACE....COMMANDS which Oracle supports!

    Or Do we have to drop the existing table and create a new one with partition!

    Thanks & Regards,

    Amit.
    Oracle DBA (OCP) v8i,v9i

  2. #2
    Join Date
    Dec 2001
    Location
    USA
    Posts
    620
    Hi,

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

    A) export/import method

    B) Insert with a subquery method

    C) Partition exchange method

    Either of these 3 methods will create a partitioned table from an existing
    non-partitioned table.

    A. Export/import method
    --------------------

    1) Export your table:

    exp usr/pswd tables=numbers file=exp.dmp

    2) Drop the table:

    drop table numbers;

    3) Recreate the table with partitions:

    create table numbers (qty 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 partbl (qty 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 partbl (qty, name)
    select * from origtbl;

    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 origtbl;
    alter table partbl rename to origtbl;

    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;
    Table created.

    SQL> 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.
    .

    Sam
    ------------------------
    To handle yourself, use your head. To handle others, use your heart

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