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-- Compos Partition

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Composite(复合) Partitioning

Composite partitioning partitions data using the range method, and within each partition, subpartitions it using the hash or list method. Composite range-hash partitioning provides the improved manageability of range partitioning and the data placement, striping, and parallelism advantages of hash partitioning. Composite range-list partitioning provides the manageability of range partitioning and the explicit control of list partitioning for the subpartitions.

Composite partitioning supports historical operations, such as adding new range partitions, but also provides higher degrees of parallelism for DML operations and finer granularity of data placement through subpartitioning.

Composite Partitioning Range-Hash Example

CREATE TABLE sales_composite (salesman_id NUMBER(5), salesman_name VARCHAR2(30), sales_amount NUMBER(10), sales_date DATE) PARTITION BY RANGE(sales_date) SUBPARTITION BY HASH(salesman_id) SUBPARTITION TEMPLATE( SUBPARTITION sp1 TABLESPACE ts1, SUBPARTITION sp2 TABLESPACE ts2, SUBPARTITION sp3 TABLESPACE ts3, SUBPARTITION sp4 TABLESPACE ts4) (PARTITION sales_jan2000 VALUES LESS THAN(TO_DATE('02/01/2000','MM/DD/YYYY')) PARTITION sales_feb2000 VALUES LESS THAN(TO_DATE('03/01/2000','MM/DD/YYYY')) PARTITION sales_mar2000 VALUES LESS THAN(TO_DATE('04/01/2000','MM/DD/YYYY')) PARTITION sales_apr2000 VALUES LESS THAN(TO_DATE('05/01/2000','MM/DD/YYYY')) PARTITION sales_may2000 VALUES LESS THAN(TO_DATE('06/01/2000','MM/DD/YYYY')));

This statement creates a table sales_composite that is range partitioned on the sales_date field and hash subpartitioned on salesman_id. When you use a template, Oracle names the subpartitions by concatenating the partition name, an underscore, and the subpartition name from the template. Oracle places this subpartition in the tablespace specified in the template. In the previous statement, sales_jan2000_sp1 is created and placed in tablespace ts1 while sales_jan2000_sp4 is created and placed in tablespace ts4. In the same manner, sales_apr2000_sp1 is created and placed in tablespace ts1 while sales_apr2000_sp4 is created and placed in tablespace ts4。

Composite Partitioning Range-List Example

CREATE TABLE bimonthly_regional_sales (deptno NUMBER, item_no VARCHAR2(20), txn_date DATE, txn_amount NUMBER, state VARCHAR2(2)) PARTITION BY RANGE (txn_date) SUBPARTITION BY LIST (state) SUBPARTITION TEMPLATE(

SUBPARTITION east VALUES('NY', 'VA', 'FL') TABLESPACE ts1, SUBPARTITION west VALUES('CA', 'OR', 'HI') TABLESPACE ts2, SUBPARTITION central VALUES('IL', 'TX', 'MO') TABLESPACE ts3)

( PARTITION janfeb_2000 VALUES LESS THAN (TO_DATE('1-MAR-2000','DD-MON-YYYY')), PARTITION marapr_2000 VALUES LESS THAN (TO_DATE('1-MAY-2000','DD-MON-YYYY')), PARTITION mayjun_2000 VALUES LESS THAN (TO_DATE('1-JUL-2000','DD-MON-YYYY')) );

This statement creates a table bimonthly_regional_sales that is range partitioned on the txn_date field and list subpartitioned on state. When you use a template, Oracle names the subpartitions by concatenating the partition name, an underscore, and the subpartition name from the template. Oracle places this subpartition in the tablespace specified in the template. In the previous statement, janfeb_2000_east is created and placed in tablespace ts1 while janfeb_2000_central is created and placed in tablespace ts3. In the same manner, mayjun_2000_east is placed in tablespace ts1 while mayjun_2000_central is placed in tablespace ts3.