一、分区概念
Oracle允许将表、索引、索引组织表细分成更小的片，每个片我们称之为分区。分区有其自己的名字和存储参数。
如下图：
每行数据只能属于一个分区，分区键决定数据行属于哪个分区。分区键由一个或多个列组成。Oracle自动的将数据的DML操作映射到相应的分区中。
何时使用分区表：
- Tables greater than 2 GB should always be considered as candidates for partitioning.
- Tables containing historical data, in which new data is added into the newest partition. A typical example is a historical table where only the current month‘s data is updatable and the other 11 months are read only.
- When the contents of a table must be distributed across different types of storage devices.
何时使用分区索引：
- Avoid rebuilding the entire index when data is removed.
- Perform maintenance on parts of the data without invalidating the entire index.
- Reduce the effect of index skew caused by an index on a column with a monotonically increasing value.
分区的优点：
分区裁剪，DML操作的数据如果可以定位到某个或者某些分区，那么只需对这部分数据进行读写。
分区智能join，如果关联查询只需用到部分分区，那么避免了全表数据的扫描。
易于维护数据。
分区策略：
LIST、RANGE、HASH、SYSTEM、INTERVAL、reference、虚拟列分区。
表分区类型：
单级别分区
组合分区
索引分区类型：
本地分区
全局分区
全局索引
二、创建分区
创建LIST分区
SQL> CREATE TABLE accounts ( id NUMBER , account_number NUMBER , customer_id NUMBER , branch_id NUMBER , region VARCHAR(2) , status VARCHAR2(1) ) PARTITION BY LIST (region) ( PARTITION p_northwest VALUES (‘OR‘, ‘WA‘) , PARTITION p_southwest VALUES (‘AZ‘, ‘UT‘, ‘NM‘) , PARTITION p_northeast VALUES (‘NY‘, ‘VM‘, ‘NJ‘) , PARTITION p_southeast VALUES (‘FL‘, ‘GA‘) , PARTITION p_northcentral VALUES (‘SD‘, ‘WI‘) , PARTITION p_southcentral VALUES (‘OK‘, ‘TX‘) ); Table created. SQL>
插入数据
SET DEFINE OFF; Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (378326946, 894594273, 1292607495, 142784215, ‘OR‘, ‘k‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (584618757, 1364130187, 438768827, 554439762, ‘WA‘, ‘o‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (41523719, 656248010, 469613013, 1849874408, ‘OR‘, ‘o‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (1484487356, 1308908163, 1088179442, 1201623497, ‘OR‘, ‘w‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (151951677, 2077813008, 139635883, 1324220110, ‘OR‘, ‘L‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (537989506, 1256709056, 5665768, 1397516214, ‘WA‘, ‘j‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (1054752157, 511468132, 2033193426, 183536554, ‘WA‘, ‘q‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (2038555798, 1761488065, 1281290484, 1134105071, ‘OR‘, ‘y‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (1749170397, 1025971133, 1336822659, 219993587, ‘OR‘, ‘G‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (1308900569, 1076156248, 496158144, 1160914382, ‘OR‘, ‘Z‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (1742657481, 1697703100, 1276715127, 249769402, ‘OR‘, ‘g‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (1730173163, 690868494, 420676729, 1001701868, ‘OR‘, ‘K‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (1113431343, 1306177470, 912447414, 39868117, ‘OR‘, ‘b‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (1813999643, 1738970302, 98672809, 54100636, ‘OR‘, ‘M‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (60561891, 1229089094, 1626776049, 1373758116, ‘OR‘, ‘l‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (1194099877, 966075960, 973792659, 106417526, ‘WA‘, ‘E‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (972828393, 1964561103, 715385951, 581092182, ‘AZ‘, ‘f‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (1387745036, 811991623, 884849418, 924597781, ‘AZ‘, ‘B‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (4042014, 1008692733, 524884932, 755313715, ‘NM‘, ‘U‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (9035402, 85439893, 333606312, 233856899, ‘UT‘, ‘j‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (300439305, 809521660, 602721207, 1167124218, ‘UT‘, ‘C‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (1261574467, 1642196402, 1309279369, 811128713, ‘AZ‘, ‘Z‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (1734634260, 1893138191, 36547218, 1696588381, ‘AZ‘, ‘d‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (1393860542, 207139753, 1053973916, 2015424087, ‘NM‘, ‘L‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (1104007962, 703835058, 1058040433, 973595416, ‘NM‘, ‘X‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (1829413354, 1360120309, 475884296, 275389923, ‘NM‘, ‘o‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (644314976, 1910013550, 770148070, 1201992324, ‘AZ‘, ‘B‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (1479078753, 501738145, 2081089479, 1365686422, ‘NM‘, ‘H‘); Insert into SCOTT.ACCOUNTS (ID, ACCOUNT_NUMBER, CUSTOMER_ID, BRANCH_ID, REGION, STATUS) Values (340748485, 1276107083, 11726459, 1736071185, ‘NM‘, ‘k‘); COMMIT;
查询分区中的数据
SQL> select count(*) from accounts; COUNT(*) ---------- 29 SQL> select count(*) from accounts partition(p_northwest); COUNT(*) ---------- 16 SQL> select count(*) from accounts PARTITION (p_southwest); COUNT(*) ---------- 13 SQL> select count(*) from accounts PARTITION (p_northeast); COUNT(*) ---------- 0
分区裁剪测试
SQL> set autotrace on SQL> select count(*) from accounts where REGION=‘AZ‘; COUNT(*) ---------- 5 Execution Plan ---------------------------------------------------------- Plan hash value: 3505378 --------------------------------------------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | Pstart| Pstop | --------------------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 1 | 3 | 14 (0)| 00:00:01 | | | | 1 | SORT AGGREGATE | | 1 | 3 | | | | | | 2 | PARTITION LIST SINGLE| | 5 | 15 | 14 (0)| 00:00:01 | KEY | KEY | |* 3 | TABLE ACCESS FULL | ACCOUNTS | 5 | 15 | 14 (0)| 00:00:01 | 2 | 2 | ---------------------------------------------------------------------------------------------------
由执行计划中可以看出，Oracle只查询了一个分区的数据。
创建RANGE分区
CREATE TABLE SALES ( PROD_ID NUMBER NOT NULL, CUST_ID NUMBER NOT NULL, TIME_ID DATE NOT NULL, CHANNEL_ID NUMBER NOT NULL, PROMO_ID NUMBER NOT NULL, QUANTITY_SOLD NUMBER(10,2) NOT NULL, AMOUNT_SOLD NUMBER(10,2) NOT NULL ) PARTITION BY RANGE (TIME_ID) ( PARTITION SALES_Q1_2003 VALUES LESS THAN (TO_DATE(‘2003-04-01 00:00:00‘, ‘YYYY-MM-DD HH24:MI:SS‘)), PARTITION SALES_Q2_2003 VALUES LESS THAN (TO_DATE(‘2003-07-01 00:00:00‘, ‘YYYY-MM-DD HH24:MI:SS‘)) , PARTITION SALES_Q3_2003 VALUES LESS THAN (TO_DATE(‘2003-10-01 00:00:00‘, ‘YYYY-MM-DD HH24:MI:SS‘)), PARTITION SALES_Q4_2003 VALUES LESS THAN (TO_DATE(‘2004-01-01 00:00:00‘, ‘YYYY-MM-DD HH24:MI:SS‘)) );
11g新增了一个时间间隔分区，本质上是RANGE分区的一个扩展。
CREATE TABLE SALES2 ( PROD_ID NUMBER NOT NULL, CUST_ID NUMBER NOT NULL, TIME_ID DATE NOT NULL, CHANNEL_ID NUMBER NOT NULL, PROMO_ID NUMBER NOT NULL, QUANTITY_SOLD NUMBER(10,2) NOT NULL, AMOUNT_SOLD NUMBER(10,2) NOT NULL ) PARTITION BY RANGE (TIME_ID) INTERVAL(NUMTOYMINTERVAL(3,‘MONTH‘)) ( PARTITION SALES_Q1_2003 VALUES LESS THAN (TO_DATE(‘2003-04-01 00:00:00‘, ‘YYYY-MM-DD HH24:MI:SS‘)) );
时间间隔分区会自动根据数据维护分区。我们做如下数据插入
SET DEFINE OFF; Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (15, 519, TO_DATE(‘01/25/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 3, 999, 1, 1003.49); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (32, 12824, TO_DATE(‘03/13/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 3, 999, 1, 73.43); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (47, 3289, TO_DATE(‘01/15/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 4, 999, 1, 29.89); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (116, 2945, TO_DATE(‘09/23/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 3, 999, 1, 14.35); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (48, 1580, TO_DATE(‘12/24/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 3, 999, 1, 13.13); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (19, 2671, TO_DATE(‘03/16/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 4, 999, 1, 52.4); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (142, 6834, TO_DATE(‘02/02/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 3, 999, 1, 25.4); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (33, 5579, TO_DATE(‘07/23/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 2, 999, 1, 45.71); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (35, 10985, TO_DATE(‘08/20/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 3, 999, 1, 59.78); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (28, 13125, TO_DATE(‘10/13/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 2, 999, 1, 203.18); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (46, 6719, TO_DATE(‘10/10/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 3, 999, 1, 25.83); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (23, 33729, TO_DATE(‘01/16/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 2, 999, 1, 23.51); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (23, 9927, TO_DATE(‘03/28/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 3, 999, 1, 23.19); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (118, 818, TO_DATE(‘01/24/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 2, 999, 1, 8.86); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (135, 5860, TO_DATE(‘02/27/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 3, 999, 1, 55.43); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (41, 2292, TO_DATE(‘04/13/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 2, 999, 1, 48.78); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (30, 7859, TO_DATE(‘07/14/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 3, 999, 1, 10.48); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (128, 3266, TO_DATE(‘07/15/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 3, 999, 1, 30.07); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (145, 3461, TO_DATE(‘10/27/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 3, 999, 1, 13.76); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (24, 9170, TO_DATE(‘02/07/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 3, 351, 1, 63.97); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (118, 1156, TO_DATE(‘01/29/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 4, 999, 1, 17.53); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (26, 11267, TO_DATE(‘06/10/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 2, 999, 1, 156.71); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (31, 8630, TO_DATE(‘04/02/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 3, 999, 1, 8.95); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (23, 392, TO_DATE(‘08/30/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 4, 999, 1, 21.22); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (47, 280, TO_DATE(‘08/13/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 2, 999, 1, 29.02); Insert into SALES2 (PROD_ID, CUST_ID, TIME_ID, CHANNEL_ID, PROMO_ID, QUANTITY_SOLD, AMOUNT_SOLD) Values (119, 6822, TO_DATE(‘08/06/2003 00:00:00‘, ‘MM/DD/YYYY HH24:MI:SS‘), 3, 999, 1, 7.31); COMMIT;
现在我们查看sales2的分区情况
SQL> SELECT TABLE_NAME, PARTITION_NAME FROM dba_tab_partitions WHERE TABLE_OWNER = ‘SCOTT‘ AND TABLE_NAME = ‘SALES2‘; TABLE_NAME PARTITION_NAME ------------------------------ ------------------------------ SALES2 SALES_Q1_2003 SALES2 SYS_P41 SALES2 SYS_P42 SALES2 SYS_P43
可见系统根据数据的实际情况，给我们新建了3个分区，分区由系统自命名。
创建HASH分区
CREATE TABLE sales_hash (s_productid NUMBER, s_saledate DATE, s_custid NUMBER, s_totalprice NUMBER) PARTITION BY HASH(s_productid) ( PARTITION p1 TABLESPACE users , PARTITION p2 TABLESPACE users , PARTITION p3 TABLESPACE users , PARTITION p4 TABLESPACE users );
根据s_productionid的值，算出hash值，将对于的数据行插入到相应的分区中。各分区数据要想分别均匀，分区的个数为2的次方数。
创建SYSTEM分区
此分区与其他的都不同，数据插入到哪个分区与数据本身无关，完全有用户自定义。
CREATE TABLE t_system ( id NUMBER, name VARCHAR2 (30) ) PARTITION BY SYSTEM (PARTITION p1, PARTITION p2, PARTITION p3, PARTITION p4);
此时往表中直接插入数据就会报错
SQL> insert into t_system(id,name)values(1,‘kevin‘); insert into t_system(id,name)values(1,‘kevin‘) * ERROR at line 1: ORA-14701: partition-extended name or bind variable must be used for DMLs on tables partitioned by the System method
插入数据，必须指定分区名称
SQL> insert into t_system partition(p1)(id,name)values(1,‘kevin‘); 1 row created.
并且重复数据可以插入到不同的分区
SQL> insert into t_system partition(p2)(id,name)values(1,‘kevin‘); 1 row created.
创建虚拟列分区
Oracle11g新增了虚拟列功能，虚拟列的值从其他的列推导而来，Oracle只保存源数据，这个列不占存储空间。虚拟列其中一个引申功能就是虚拟列分区功能。11g增加对虚拟列的支持，这使得分区功能更加灵活。如：表中有一个日期列，希望根据日期列进行分区，每个月份一个分区，总共12个分区，不管是哪一年的，只要是那个月，就放在那个月的分区中。
CREATE TABLE T_PARTITION_MONTH ( ID NUMBER, NAME VARCHAR2 (30), CREATE_DATE DATE, PARTITION_MONTH AS (TO_NUMBER (TO_CHAR (CREATE_DATE, ‘MM‘))) ) PARTITION BY LIST (PARTITION_MONTH) ( PARTITION P1 VALUES (1), PARTITION P2 VALUES (2), PARTITION P3 VALUES (3), PARTITION P4 VALUES (4), PARTITION P5 VALUES (5), PARTITION P6 VALUES (6), PARTITION P7 VALUES (7), PARTITION P8 VALUES (8), PARTITION P9 VALUES (9), PARTITION P10 VALUES (10), PARTITION P11 VALUES (11), PARTITION P12 VALUES (12));
创建参考列分区
子表的分区依赖于父表，我们看如下例子
CREATE TABLE orders ( order_id NUMBER(12), order_date TIMESTAMP, order_mode VARCHAR2(8), customer_id NUMBER(6), order_status NUMBER(2), order_total NUMBER(8,2), sales_rep_id NUMBER(6), promotion_id NUMBER(6), CONSTRAINT orders_pk PRIMARY KEY(order_id) ) PARTITION BY RANGE(order_date) ( PARTITION Q1_2005 VALUES LESS THAN (TO_DATE(‘01-APR-2005‘,‘DD-MON-YYYY‘)), PARTITION Q2_2005 VALUES LESS THAN (TO_DATE(‘01-JUL-2005‘,‘DD-MON-YYYY‘)), PARTITION Q3_2005 VALUES LESS THAN (TO_DATE(‘01-OCT-2005‘,‘DD-MON-YYYY‘)), PARTITION Q4_2005 VALUES LESS THAN (TO_DATE(‘01-JAN-2006‘,‘DD-MON-YYYY‘)) );
订单表，按order_date做范围分区。
CREATE TABLE order_items ( order_id NUMBER(12) NOT NULL, line_item_id NUMBER(3) NOT NULL, product_id NUMBER(6) NOT NULL, unit_price NUMBER(8,2), quantity NUMBER(8), CONSTRAINT order_items_fk FOREIGN KEY(order_id) REFERENCES orders(order_id) ) PARTITION BY REFERENCE(order_items_fk);
订单项目表，该表分区参考主表。
查看order_items的分区信息
SQL> SELECT TABLE_NAME, PARTITION_NAME FROM DBA_TAB_PARTITIONS WHERE TABLE_NAME = ‘ORDER_ITEMS‘; TABLE_NAME PARTITION_NAME ------------------------------ ------------------------------ ORDER_ITEMS Q1_2005 ORDER_ITEMS Q2_2005 ORDER_ITEMS Q3_2005 ORDER_ITEMS Q4_2005
对于range和hash分区，你可以指定多列作为分区键。列数最多16个。
CREATE TABLE sales_demo ( year NUMBER, month NUMBER, day NUMBER, amount_sold NUMBER) PARTITION BY RANGE (year,month) (PARTITION before2001 VALUES LESS THAN (2001,1), PARTITION q1_2001 VALUES LESS THAN (2001,4), PARTITION q2_2001 VALUES LESS THAN (2001,7), PARTITION q3_2001 VALUES LESS THAN (2001,10), PARTITION q4_2001 VALUES LESS THAN (2002,1), PARTITION future VALUES LESS THAN (MAXVALUE,0)); REM 12-DEC-2000 INSERT INTO sales_demo VALUES(2000,12,12, 1000); REM 17-MAR-2001 INSERT INTO sales_demo VALUES(2001,3,17, 2000); REM 1-NOV-2001 INSERT INTO sales_demo VALUES(2001,11,1, 5000); REM 1-JAN-2002 INSERT INTO sales_demo VALUES(2002,1,1, 4000);
组合分区有如下六种：
RANGE-RANGE、RANGE-LIST、RANGE-HASH、LIST-RANGE、LIST-LIST、LIST-HASH 。
组合分区的创建与单分区类似。
创建RANGE-RANGE组合分区
CREATE TABLE shipments ( order_id NUMBER NOT NULL , order_date DATE NOT NULL , delivery_date DATE NOT NULL , customer_id NUMBER NOT NULL , sales_amount NUMBER NOT NULL ) PARTITION BY RANGE (order_date) SUBPARTITION BY RANGE (delivery_date) ( PARTITION p_2006_jul VALUES LESS THAN (TO_DATE(‘01-AUG-2006‘,‘dd-MON-yyyy‘)) ( SUBPARTITION p06_jul_e VALUES LESS THAN (TO_DATE(‘15-AUG-2006‘,‘dd-MON-yyyy‘)) , SUBPARTITION p06_jul_a VALUES LESS THAN (TO_DATE(‘01-SEP-2006‘,‘dd-MON-yyyy‘)) , SUBPARTITION p06_jul_l VALUES LESS THAN (MAXVALUE) ) , PARTITION p_2006_aug VALUES LESS THAN (TO_DATE(‘01-SEP-2006‘,‘dd-MON-yyyy‘)) ( SUBPARTITION p06_aug_e VALUES LESS THAN (TO_DATE(‘15-SEP-2006‘,‘dd-MON-yyyy‘)) , SUBPARTITION p06_aug_a VALUES LESS THAN (TO_DATE(‘01-OCT-2006‘,‘dd-MON-yyyy‘)) , SUBPARTITION p06_aug_l VALUES LESS THAN (MAXVALUE) ) , PARTITION p_2006_sep VALUES LESS THAN (TO_DATE(‘01-OCT-2006‘,‘dd-MON-yyyy‘)) ( SUBPARTITION p06_sep_e VALUES LESS THAN (TO_DATE(‘15-OCT-2006‘,‘dd-MON-yyyy‘)) , SUBPARTITION p06_sep_a VALUES LESS THAN (TO_DATE(‘01-NOV-2006‘,‘dd-MON-yyyy‘)) , SUBPARTITION p06_sep_l VALUES LESS THAN (MAXVALUE) ) , PARTITION p_2006_oct VALUES LESS THAN (TO_DATE(‘01-NOV-2006‘,‘dd-MON-yyyy‘)) ( SUBPARTITION p06_oct_e VALUES LESS THAN (TO_DATE(‘15-NOV-2006‘,‘dd-MON-yyyy‘)) , SUBPARTITION p06_oct_a VALUES LESS THAN (TO_DATE(‘01-DEC-2006‘,‘dd-MON-yyyy‘)) , SUBPARTITION p06_oct_l VALUES LESS THAN (MAXVALUE) ) , PARTITION p_2006_nov VALUES LESS THAN (TO_DATE(‘01-DEC-2006‘,‘dd-MON-yyyy‘)) ( SUBPARTITION p06_nov_e VALUES LESS THAN (TO_DATE(‘15-DEC-2006‘,‘dd-MON-yyyy‘)) , SUBPARTITION p06_nov_a VALUES LESS THAN (TO_DATE(‘01-JAN-2007‘,‘dd-MON-yyyy‘)) , SUBPARTITION p06_nov_l VALUES LESS THAN (MAXVALUE) ) , PARTITION p_2006_dec VALUES LESS THAN (TO_DATE(‘01-JAN-2007‘,‘dd-MON-yyyy‘)) ( SUBPARTITION p06_dec_e VALUES LESS THAN (TO_DATE(‘15-JAN-2007‘,‘dd-MON-yyyy‘)) , SUBPARTITION p06_dec_a VALUES LESS THAN (TO_DATE(‘01-FEB-2007‘,‘dd-MON-yyyy‘)) , SUBPARTITION p06_dec_l VALUES LESS THAN (MAXVALUE) ) );
查看分区信息
SQL> SELECT TABLE_NAME, PARTITION_NAME,SUBPARTITION_COUNT FROM DBA_TAB_PARTITIONS WHERE TABLE_NAME = ‘SHIPMENTS‘; TABLE_NAME PARTITION_NAME SUBPARTITION_COUNT ------------------------------ ------------------------------ ------------------ SHIPMENTS P_2006_JUL 3 SHIPMENTS P_2006_AUG 3 SHIPMENTS P_2006_SEP 3 SHIPMENTS P_2006_OCT 3 SHIPMENTS P_2006_NOV 3 SHIPMENTS P_2006_DEC 3 6 rows selected.
查看子分区信息
SQL> SELECT TABLE_NAME, PARTITION_NAME,SUBPARTITION_NAME FROM DBA_TAB_SUBPARTITIONS WHERE TABLE_NAME = ‘SHIPMENTS‘; TABLE_NAME PARTITION_NAME SUBPARTITION_NAME ------------------------------ ------------------------------ ------------------------------ SHIPMENTS P_2006_DEC P06_DEC_E SHIPMENTS P_2006_DEC P06_DEC_A SHIPMENTS P_2006_DEC P06_DEC_L SHIPMENTS P_2006_NOV P06_NOV_E SHIPMENTS P_2006_NOV P06_NOV_A SHIPMENTS P_2006_NOV P06_NOV_L SHIPMENTS P_2006_OCT P06_OCT_E SHIPMENTS P_2006_OCT P06_OCT_A SHIPMENTS P_2006_OCT P06_OCT_L SHIPMENTS P_2006_SEP P06_SEP_E SHIPMENTS P_2006_SEP P06_SEP_A TABLE_NAME PARTITION_NAME SUBPARTITION_NAME ------------------------------ ------------------------------ ------------------------------ SHIPMENTS P_2006_SEP P06_SEP_L SHIPMENTS P_2006_AUG P06_AUG_E SHIPMENTS P_2006_AUG P06_AUG_A SHIPMENTS P_2006_AUG P06_AUG_L SHIPMENTS P_2006_JUL P06_JUL_E SHIPMENTS P_2006_JUL P06_JUL_A SHIPMENTS P_2006_JUL P06_JUL_L 18 rows selected.
创建RANGE-LIST
CREATE TABLE quarterly_regional_sales (deptno number, item_no varchar2(20), txn_date date, txn_amount number, state varchar2(2)) TABLESPACE ts4 PARTITION BY RANGE (txn_date) SUBPARTITION BY LIST (state) (PARTITION q1_1999 VALUES LESS THAN (TO_DATE(‘1-APR-1999‘,‘DD-MON-YYYY‘)) (SUBPARTITION q1_1999_northwest VALUES (‘OR‘, ‘WA‘), SUBPARTITION q1_1999_southwest VALUES (‘AZ‘, ‘UT‘, ‘NM‘), SUBPARTITION q1_1999_northeast VALUES (‘NY‘, ‘VM‘, ‘NJ‘), SUBPARTITION q1_1999_southeast VALUES (‘FL‘, ‘GA‘), SUBPARTITION q1_1999_northcentral VALUES (‘SD‘, ‘WI‘), SUBPARTITION q1_1999_southcentral VALUES (‘OK‘, ‘TX‘) ), PARTITION q2_1999 VALUES LESS THAN ( TO_DATE(‘1-JUL-1999‘,‘DD-MON-YYYY‘)) (SUBPARTITION q2_1999_northwest VALUES (‘OR‘, ‘WA‘), SUBPARTITION q2_1999_southwest VALUES (‘AZ‘, ‘UT‘, ‘NM‘), SUBPARTITION q2_1999_northeast VALUES (‘NY‘, ‘VM‘, ‘NJ‘), SUBPARTITION q2_1999_southeast VALUES (‘FL‘, ‘GA‘), SUBPARTITION q2_1999_northcentral VALUES (‘SD‘, ‘WI‘), SUBPARTITION q2_1999_southcentral VALUES (‘OK‘, ‘TX‘) ), PARTITION q3_1999 VALUES LESS THAN (TO_DATE(‘1-OCT-1999‘,‘DD-MON-YYYY‘)) (SUBPARTITION q3_1999_northwest VALUES (‘OR‘, ‘WA‘), SUBPARTITION q3_1999_southwest VALUES (‘AZ‘, ‘UT‘, ‘NM‘), SUBPARTITION q3_1999_northeast VALUES (‘NY‘, ‘VM‘, ‘NJ‘), SUBPARTITION q3_1999_southeast VALUES (‘FL‘, ‘GA‘), SUBPARTITION q3_1999_northcentral VALUES (‘SD‘, ‘WI‘), SUBPARTITION q3_1999_southcentral VALUES (‘OK‘, ‘TX‘) ), PARTITION q4_1999 VALUES LESS THAN ( TO_DATE(‘1-JAN-2000‘,‘DD-MON-YYYY‘)) (SUBPARTITION q4_1999_northwest VALUES (‘OR‘, ‘WA‘), SUBPARTITION q4_1999_southwest VALUES (‘AZ‘, ‘UT‘, ‘NM‘), SUBPARTITION q4_1999_northeast VALUES (‘NY‘, ‘VM‘, ‘NJ‘), SUBPARTITION q4_1999_southeast VALUES (‘FL‘, ‘GA‘), SUBPARTITION q4_1999_northcentral VALUES (‘SD‘, ‘WI‘), SUBPARTITION q4_1999_southcentral VALUES (‘OK‘, ‘TX‘) ) );
创建RANGE-HASH分区
CREATE TABLE sales ( prod_id NUMBER(6) , cust_id NUMBER , time_id DATE , channel_id CHAR(1) , promo_id NUMBER(6) , quantity_sold NUMBER(3) , amount_sold NUMBER(10,2) ) PARTITION BY RANGE (time_id) SUBPARTITION BY HASH (cust_id) SUBPARTITIONS 8 STORE IN (ts1, ts2, ts3, ts4) ( PARTITION sales_q1_2006 VALUES LESS THAN (TO_DATE(‘01-APR-2006‘,‘dd-MON-yyyy‘)) , PARTITION sales_q2_2006 VALUES LESS THAN (TO_DATE(‘01-JUL-2006‘,‘dd-MON-yyyy‘)) , PARTITION sales_q3_2006 VALUES LESS THAN (TO_DATE(‘01-OCT-2006‘,‘dd-MON-yyyy‘)) , PARTITION sales_q4_2006 VALUES LESS THAN (TO_DATE(‘01-JAN-2007‘,‘dd-MON-yyyy‘)) );
子分区也可以指定模板
如下：
CREATE TABLE sales_range_range ( prod_id NUMBER(6) , cust_id NUMBER , time_id DATE , channel_id CHAR(1) , promo_id NUMBER(6) , quantity_sold NUMBER(3) , amount_sold NUMBER(10,2) ) PARTITION BY RANGE (time_id) INTERVAL (NUMTODSINTERVAL(1,‘DAY‘)) SUBPARTITION BY RANGE(amount_sold) SUBPARTITION TEMPLATE ( SUBPARTITION p_low VALUES LESS THAN (1000) , SUBPARTITION p_medium VALUES LESS THAN (4000) , SUBPARTITION p_high VALUES LESS THAN (8000) , SUBPARTITION p_ultimate VALUES LESS THAN (maxvalue) ) ( PARTITION before_2000 VALUES LESS THAN (TO_DATE(‘01-JAN-2000‘,‘dd-MON-yyyy‘))) 或者 CREATE TABLE sales_range_range ( prod_id NUMBER(6) , cust_id NUMBER , time_id DATE , channel_id CHAR(1) , promo_id NUMBER(6) , quantity_sold NUMBER(3) , amount_sold NUMBER(10,2) ) PARTITION BY RANGE (time_id) SUBPARTITION BY RANGE(amount_sold) SUBPARTITION TEMPLATE ( SUBPARTITION p_low VALUES LESS THAN (1000) , SUBPARTITION p_medium VALUES LESS THAN (4000) , SUBPARTITION p_high VALUES LESS THAN (8000) , SUBPARTITION p_ultimate VALUES LESS THAN (maxvalue) ) ( PARTITION before_2000 VALUES LESS THAN (TO_DATE(‘01-JAN-2000‘,‘dd-MON-yyyy‘)))
CREATE TABLE emp_sub_template (deptno NUMBER, empname VARCHAR(32), grade NUMBER) PARTITION BY RANGE(deptno) SUBPARTITION BY HASH(empname) SUBPARTITION TEMPLATE (SUBPARTITION a TABLESPACE ts1, SUBPARTITION b TABLESPACE ts2, SUBPARTITION c TABLESPACE ts3, SUBPARTITION d TABLESPACE ts4 ) (PARTITION p1 VALUES LESS THAN (1000), PARTITION p2 VALUES LESS THAN (2000), PARTITION p3 VALUES LESS THAN (MAXVALUE) );
CREATE TABLE stripe_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 northwest VALUES (‘OR‘, ‘WA‘) TABLESPACE tbs_1, SUBPARTITION southwest VALUES (‘AZ‘, ‘UT‘, ‘NM‘) TABLESPACE tbs_2, SUBPARTITION northeast VALUES (‘NY‘, ‘VM‘, ‘NJ‘) TABLESPACE tbs_3, SUBPARTITION southeast VALUES (‘FL‘, ‘GA‘) TABLESPACE tbs_4, SUBPARTITION midwest VALUES (‘SD‘, ‘WI‘) TABLESPACE tbs_5, SUBPARTITION south VALUES (‘AL‘, ‘AK‘) TABLESPACE tbs_6, SUBPARTITION others VALUES (DEFAULT ) TABLESPACE tbs_7 ) (PARTITION q1_1999 VALUES LESS THAN ( TO_DATE(‘01-APR-1999‘,‘DD-MON-YYYY‘)), PARTITION q2_1999 VALUES LESS THAN ( TO_DATE(‘01-JUL-1999‘,‘DD-MON-YYYY‘)), PARTITION q3_1999 VALUES LESS THAN ( TO_DATE(‘01-OCT-1999‘,‘DD-MON-YYYY‘)), PARTITION q4_1999 VALUES LESS THAN ( TO_DATE(‘1-JAN-2000‘,‘DD-MON-YYYY‘)) );
创建分区索引
本地索引
SQL> create index idx_accounts_number on accounts(account_number) local; Index created.
创建索引时，添加local关键字，即为表的每个分区单独创建一个索引。
SQL> select index_name,partition_name from dba_ind_partitions where index_name=‘IDX_ACCOUNTS_NUMBER‘; INDEX_NAME PARTITION_NAME ------------------------------ ------------------------------ IDX_ACCOUNTS_NUMBER P_NORTHCENTRAL IDX_ACCOUNTS_NUMBER P_NORTHEAST IDX_ACCOUNTS_NUMBER P_NORTHWEST IDX_ACCOUNTS_NUMBER P_SOUTHCENTRAL IDX_ACCOUNTS_NUMBER P_SOUTHEAST IDX_ACCOUNTS_NUMBER P_SOUTHWEST 6 rows selected.
可见，表有几个分区，就创建几个索引分区。
全局索引
创建方法与普通索引一致。
SQL> create index idx_accounts_id on accounts(id); Index created.
SQL> select index_name,partition_name from dba_ind_partitions where index_name=‘IDX_ACCOUNTS_ID‘; no rows selected
索引没有分区。
全局分区索引
SQL> create index idx_accounts_customer_id on accounts(customer_id) global partition by hash(customer_id) partitions 4; Index created.
SQL> select index_name,partition_name from dba_ind_partitions where index_name=‘IDX_ACCOUNTS_CUSTOMER_ID‘; INDEX_NAME PARTITION_NAME ------------------------------ ------------------------------ IDX_ACCOUNTS_CUSTOMER_ID SYS_P61 IDX_ACCOUNTS_CUSTOMER_ID SYS_P62 IDX_ACCOUNTS_CUSTOMER_ID SYS_P63 IDX_ACCOUNTS_CUSTOMER_ID SYS_P64
三、维护分区
添加分区
LIST分区
SQL> ALTER TABLE accounts ADD PARTITION p_nonmainland VALUES (‘HI‘, ‘PR‘); Table altered. SQL>
RANGE分区
SQL> ALTER TABLE sales ADD PARTITION sale_q1_2004 VALUES LESS THAN (TO_DATE (‘2004-04-01 00:00:00‘, ‘YYYY-MM-DD HH24:MI:SS‘)); Table altered. SQL>
HASH分区
SQL> ALTER TABLE sales_hash ADD PARTITION; Table altered.
对于组合分区
SQL> ALTER TABLE shipments ADD PARTITION p_2007_jan VALUES LESS THAN (TO_DATE(‘01-FEB-2007‘,‘dd-MON-yyyy‘)); Table altered.
如果添加分区时，不指定子分区，那么系统默认帮你建立一个子分区
SQL> SELECT TABLE_NAME, PARTITION_NAME,SUBPARTITION_NAME FROM DBA_TAB_SUBPARTITIONS WHERE TABLE_NAME = ‘SHIPMENTS‘ and PARTITION_NAME=‘P_2007_JAN‘; TABLE_NAME PARTITION_NAME SUBPARTITION_NAME ------------------------------ ------------------------------ ------------------------------ SHIPMENTS P_2007_JAN SYS_SUBP82
添加分区时，也可以指定子分区
SQL> ALTER TABLE shipments ADD PARTITION p_2008_jan VALUES LESS THAN (TO_DATE(‘01-FEB-2008‘,‘dd-MON-yyyy‘)) ( SUBPARTITION p07_jan_e VALUES LESS THAN (TO_DATE(‘15-FEB-2007‘,‘dd-MON-yyyy‘)) , SUBPARTITION p07_jan_a VALUES LESS THAN (TO_DATE(‘01-MAR-2007‘,‘dd-MON-yyyy‘)) , SUBPARTITION p07_jan_l VALUES LESS THAN (TO_DATE(‘01-APR-2007‘,‘dd-MON-yyyy‘)) ) ; Table altered.
此时子分区信息如下
SQL> SELECT TABLE_NAME, PARTITION_NAME,SUBPARTITION_NAME FROM DBA_TAB_SUBPARTITIONS WHERE TABLE_NAME = ‘SHIPMENTS‘ and PARTITION_NAME=‘P_2008_JAN‘; TABLE_NAME PARTITION_NAME SUBPARTITION_NAME ------------------------------ ------------------------------ ------------------------------ SHIPMENTS P_2008_JAN P07_JAN_E SHIPMENTS P_2008_JAN P07_JAN_A SHIPMENTS P_2008_JAN P07_JAN_L
如果组合分区的子分区指定了模板，那么添加分区时，无需指定子分区。
SQL> ALTER TABLE SALES_RANGE_RANGE ADD PARTITION P_2000 VALUES LESS THAN (TO_DATE (‘01-JAN-2001‘, ‘dd-MON-yyyy‘)); Table altered.
查看分区信息
SQL> SELECT TABLE_NAME, PARTITION_NAME,SUBPARTITION_NAME FROM DBA_TAB_SUBPARTITIONS WHERE TABLE_NAME = ‘SALES_RANGE_RANGE‘ and PARTITION_NAME=‘P_2000‘; TABLE_NAME PARTITION_NAME SUBPARTITION_NAME ------------------------------ ------------------------------ ------------------------------ SALES_RANGE_RANGE P_2000 P_2000_P_LOW SALES_RANGE_RANGE P_2000 P_2000_P_MEDIUM SALES_RANGE_RANGE P_2000 P_2000_P_HIGH SALES_RANGE_RANGE P_2000 P_2000_P_ULTIMATE
删除分区
Use one of the following statements to drop a table partition or subpartition:
ALTERTABLE...DROPPARTITIONto drop a table partitionALTERTABLE...DROPSUBPARTITIONto drop a subpartition of a composite *-[range | list] partitioned table
SQL> ALTER TABLE SALES DROP PARTITION SALE_Q1_2004; Table altered.
删除子分区
SQL> alter table sales_range_range drop subpartition P_2000_P_LOW; Table altered.
hash分区是不能被删除的
SQL> ALTER TABLE SALES_HASH DROP PARTITION SYS_P81; ALTER TABLE SALES_HASH DROP PARTITION SYS_P81 * ERROR at line 1: ORA-14255: table is not partitioned by Range, List, Composite Range or Composite List method
hash分区需要使用COALESCE关键字合并分区
SQL> SELECT TABLE_NAME, PARTITION_NAME,SUBPARTITION_COUNT FROM DBA_TAB_PARTITIONS WHERE TABLE_NAME = ‘SALES_HASH‘; 2 3 TABLE_NAME PARTITION_NAME SUBPARTITION_COUNT ------------------------------ ------------------------------ ------------------ SALES_HASH P1 0 SALES_HASH P2 0 SALES_HASH P3 0 SALES_HASH P4 0 SALES_HASH SYS_P81 0 SQL> ALTER TABLE SALES_HASH COALESCE PARTITION; Table altered. SQL> SELECT TABLE_NAME, PARTITION_NAME,SUBPARTITION_COUNT FROM DBA_TAB_PARTITIONS WHERE TABLE_NAME = ‘SALES_HASH‘; 2 3 TABLE_NAME PARTITION_NAME SUBPARTITION_COUNT ------------------------------ ------------------------------ ------------------ SALES_HASH P1 0 SALES_HASH P2 0 SALES_HASH P3 0 SALES_HASH P4 0
删除hash子分区用如下语法
ALTER TABLE diving MODIFY PARTITION us_locations COALESCE SUBPARTITION;
分区交换
exchange partition是用来将分区表与普通表之间做转换。但是普通表只能和分区表中的某个分区做交换。而不能简单的将普通表变成分区表。
CREATE TABLE t ( empno NUMBER, sal NUMBER ) PARTITION BY RANGE (sal) ( PARTITION sal_less_3000 VALUES LESS THAN (3000), PARTITION sal_between_3000_5000 VALUES LESS THAN (5000));
生成两个普通表
SQL> create table t_part1 as select empno,sal from emp where sal<3000; Table created. SQL> create table t_part2 as select empno,sal from emp where sal>=3000 and sal<5000; Table created.
查看表的data_object_id
SQL> COL OBJECT_NAME FOR A30 SQL> COL SUBOBJECT_NAME FOR A30 SQL> select OBJECT_NAME,SUBOBJECT_NAME,OBJECT_ID,DATA_OBJECT_ID from dba_objects where object_name in (‘T‘,‘T_PART1‘,‘T_PART2‘); OBJECT_NAME SUBOBJECT_NAME OBJECT_ID DATA_OBJECT_ID ------------------------------ ------------------------------ ---------- -------------- T SAL_LESS_3000 88777 88777 T 88776 T_PART2 88775 88775 T_PART1 88774 88774 T SAL_BETWEEN_3000_5000 88778 88778
进行分区交换
SQL> alter table t exchange partition sal_less_3000 with table t_part1; Table altered. SQL> alter table t exchange partition sal_between_3000_5000 with table t_part2; Table altered. SQL> select count(*) from t; COUNT(*) ---------- 26
再次查看data_object_id
SQL> select OBJECT_NAME,SUBOBJECT_NAME,OBJECT_ID,DATA_OBJECT_ID from dba_objects where object_name in (‘T‘,‘T_PART1‘,‘T_PART2‘); OBJECT_NAME SUBOBJECT_NAME OBJECT_ID DATA_OBJECT_ID ------------------------------ ------------------------------ ---------- -------------- T SAL_LESS_3000 88777 88774 T 88776 T_PART2 88775 88778 T_PART1 88774 88777 T SAL_BETWEEN_3000_5000 88778 88775
可见t_part1、t_part2的data_object_id与分区的值发生了对调。交换分区执行修改了数据字典的内容。效率非常高。
子分区也可以发生交换，请参考官方文档。
分区合并
将两个分区合并成一个分区，hash分区例外
SQL> alter table accounts merge partitions p_northcentral ,p_southcentral into partition p_central; Table altered.
如果是interval分区，可以使用如下语法
ALTER TABLE transactions MERGE PARTITIONS FOR(TO_DATE(‘15-JAN-2007‘,‘dd-MON-yyyy‘)) , FOR(TO_DATE(‘16-JAN-2007‘,‘dd-MON-yyyy‘));
分区拆分
LIST分区
ALTER TABLE sales_by_region SPLIT PARTITION region_east VALUES (‘CT‘, ‘MA‘, ‘MD‘) INTO ( PARTITION region_east_1 TABLESPACE tbs2, PARTITION region_east_2 STORAGE (INITIAL 8M)) PARALLEL 5;
The literal value list for the original region_east partition was specified as:
PARTITION region_east VALUES (‘MA‘,‘NY‘,‘CT‘,‘NH‘,‘ME‘,‘MD‘,‘VA‘,‘PA‘,‘NJ‘)
The two new partitions are:
region_east_1with a literal value list of(‘CT‘,‘MA‘,‘MD‘)region_east_2inheriting the remaining literal value list of(‘NY‘,‘NH‘,‘ME‘,‘VA‘,‘PA‘,‘NJ‘)
范围分区
ALTER TABLE vet_cats SPLIT PARTITION fee_katy at (100) INTO ( PARTITION fee_katy1, PARTITION fee_katy2);
假设fee_katy分区的取值为[90-110)，那么新拆分的两个分区的取值为fee_katy1=[90-100),fee_katy2=[100-110) .
时间间隔分区
ALTER TABLE transactions SPLIT PARTITION FOR(TO_DATE(‘01-MAY-2007‘,‘dd-MON-yyyy‘)) AT (TO_DATE(‘15-MAY-2007‘,‘dd-MON-yyyy‘));
时间： 2024-10-12 16:00:09