INTERVAL分区其实是一种比较特殊的范围分区，因此可以很方便的将RANGE分区表转化为INTERVAL分区表，同样可以将INTERVAL分区表转化为RANGE分区表。
对于一个普通的范围分区表：
SQL> CREATE TABLE T_PART
2 (ID NUMBER,
3 NAME VARCHAR2(30),
4 CREATE_DATE DATE)
5 PARTITION BY RANGE (ID)
6 (PARTITION P1 VALUES LESS THAN (100),
7 PARTITION P2 VALUES LESS THAN (200),
8 PARTITION P3 VALUES LESS THAN (300));
表已创建。
SQL> SELECT TABLE_NAME, PARTITIONING_TYPE, INTERVAL
2 FROM USER_PART_TABLES
3 WHERE TABLE_NAME = 'T_PART';
TABLE_NAME PARTITION INTERVAL
------------------------------ --------- ----------------------------------------
T_PART RANGE
SQL> INSERT INTO T_PART
2 VALUES (100, 'A', SYSDATE);
已创建1行。
SQL> INSERT INTO T_PART
2 VALUES (240, 'A', SYSDATE);
已创建1行。
SQL> INSERT INTO T_PART
2 VALUES (360, 'TEST', SYSDATE);
INSERT INTO T_PART
*
第1行出现错误:
ORA-14400:插入的分区关键字未映射到任何分区
插入超过分区上限的记录会报错，下面通过一个简单ALTER TABLE语句，将RANGE分区表转化为INTERVAL分区表：
SQL> ALTER TABLE T_PART SET INTERVAL (100);
表已更改。
SQL> SELECT TABLE_NAME, PARTITIONING_TYPE, INTERVAL
2 FROM USER_PART_TABLES
3 WHERE TABLE_NAME = 'T_PART';
TABLE_NAME PARTITION INTERVAL
------------------------------ --------- ----------------------------------------
T_PART RANGE 100
SQL> INSERT INTO T_PART
2 VALUES (360, 'TEST', SYSDATE);
已创建1行。
SQL> COMMIT;
提交完成。
SQL> SELECT TABLE_NAME, PARTITION_NAME, HIGH_VALUE
2 FROM USER_TAB_PARTITIONS
3 WHERE TABLE_NAME = 'T_PART';
TABLE_NAME PARTITION_NAME HIGH_VALUE
------------------------------ ------------------------------ ----------------------
T_PART P1 100
T_PART P2 200
T_PART P3 300
T_PART SYS_P97 400
对于INTERVAL分区表，新增的超过分区上限的数据会自动导致对应的INTERVAL分区被建立。
同样INTERVAL分区表可以方便的转化为RANGE分区表，只需要不输入INTERVAL的值即可：
SQL> ALTER TABLE T_PART SET INTERVAL ();
表已更改。
SQL> SELECT TABLE_NAME, PARTITIONING_TYPE, INTERVAL
2 FROM USER_PART_TABLES
3 WHERE TABLE_NAME = 'T_PART';
TABLE_NAME PARTITION INTERVAL
------------------------------ --------- ----------------------------------------
T_PART RANGE
SQL> INSERT INTO T_PART
2 VALUES (450, 'B', SYSDATE);
INSERT INTO T_PART
*
第1行出现错误:
ORA-14400:插入的分区关键字未映射到任何分区
同时需要注意，不输入INTERVAL的值不等价于输入NULL：
SQL> ALTER TABLE T_PART SET INTERVAL (NULL);
ALTER TABLE T_PART SET INTERVAL (NULL)
*
第1行出现错误:
ORA-14752:间隔表达式不是正确类型的常数
除了RANGE分区表和INTERVAL分区表之间可以相互转化，INTERVAL分区也可以转化为RANGE分区：
SQL> ALTER TABLE T_PART SET INTERVAL (100);
表已更改。
SQL> SELECT TABLE_NAME, PARTITION_NAME, HIGH_VALUE, INTERVAL
2 FROM USER_TAB_PARTITIONS
3 WHERE TABLE_NAME = 'T_PART';
TABLE_NAME PARTITION_NAME HIGH_VALUE INTERVAL
---------- --------------- ---------------------------------------- ----------------------
T_PART P1 100 NO
T_PART P2 200 NO
T_PART P3 300 NO
T_PART SYS_P97 400 NO
SQL> INSERT INTO T_PART
2 VALUES (453, 'A', SYSDATE);
已创建1行。
SQL> INSERT INTO T_PART
2 VALUES (743, 'B', SYSDATE);
已创建1行。
SQL> COMMIT;
提交完成。
SQL> SELECT TABLE_NAME, PARTITION_NAME, HIGH_VALUE, INTERVAL
2 FROM USER_TAB_PARTITIONS
3 WHERE TABLE_NAME = 'T_PART';
TABLE_NAME PARTITION_NAME HIGH_VALUE INTERVAL
---------- --------------- ---------------------------------------- --------------------
T_PART P1 100 NO
T_PART P2 200 NO
T_PART P3 300 NO
T_PART SYS_P97 400 NO
T_PART SYS_P98 500 YES
T_PART SYS_P99 800 YES
已选择6行。
除了MERGE PARTITION、SPLIT PARTITION之外，直接修改分区表为RANGE分区，也会使得所有现存的INTERVAL分区变成RANGE分区：
SQL> SELECT DBMS_METADATA.GET_DDL('TABLE', 'T_PART')
2 FROM DUAL;
DBMS_METADATA.GET_DDL('TABLE','T_PART')
--------------------------------------------------------------------------------
CREATE TABLE "YANGTK"."T_PART"
( "ID" NUMBER,
"NAME" VARCHAR2(30),
"CREATE_DATE" DATE
) PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255
STORAGE(
BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
TABLESPACE "YANGTK"
PARTITION BY RANGE ("ID") INTERVAL (100)
(PARTITION "P1" VALUES LESS THAN (100)
PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255
STORAGE(INITIAL 81920 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE
DEFAULT)
TABLESPACE "YANGTK" NOCOMPRESS ,
PARTITION "P2" VALUES LESS THAN (200)
PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255
STORAGE(INITIAL 81920 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
TABLESPACE "YANGTK" NOCOMPRESS ,
PARTITION "P3" VALUES LESS THAN (300)
PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255
STORAGE(INITIAL 81920 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFA
ULT CELL_FLASH_CACHE DEFAULT)
TABLESPACE "YANGTK" NOCOMPRESS ,
PARTITION "SYS_P97" VALUES LESS THAN (400)
PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255
STORAGE(INITIAL 81920 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT C
ELL_FLASH_CACHE DEFAULT)
TABLESPACE "YANGTK" NOCOMPRESS )
SQL> ALTER TABLE T_PART SET INTERVAL ();
表已更改。
SQL> SELECT TABLE_NAME, PARTITION_NAME, HIGH_VALUE, INTERVAL
2 FROM USER_TAB_PARTITIONS
3 WHERE TABLE_NAME = 'T_PART';
TABLE_NAME PARTITION_NAME HIGH_VALUE INTERVAL
---------- --------------- ---------------------------------------- ----------------
T_PART P1 100 NO
T_PART P2 200 NO
T_PART P3 300 NO
T_PART SYS_P97 400 NO
T_PART SYS_P98 500 NO
T_PART SYS_P99 800 NO
已选择6行。
SQL> SELECT DBMS_METADATA.GET_DDL('TABLE', 'T_PART')
2 FROM DUAL;
DBMS_METADATA.GET_DDL('TABLE','T_PART')
--------------------------------------------------------------------------------
CREATE TABLE "YANGTK"."T_PART"
( "ID" NUMBER,
"NAME" VARCHAR2(30),
"CREATE_DATE" DATE
) PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255
STORAGE(
BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
TABLESPACE "YANGTK"
PARTITION BY RANGE ("ID")
(PARTITION "P1" VALUES LESS THAN (100)
PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255
STORAGE(INITIAL 81920 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
TABLESPACE "YANGTK" NOCOMPRESS ,
PARTITION "P2" VALUES LESS THAN (200)
PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255
STORAGE(INITIAL 81920 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT C
ELL_FLASH_CACHE DEFAULT)
TABLESPACE "YANGTK" NOCOMPRESS ,
PARTITION "P3" VALUES LESS THAN (300)
PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255
STORAGE(INITIAL 81920 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_
CACHE DEFAULT)
TABLESPACE "YANGTK" NOCOMPRESS ,
PARTITION "SYS_P97" VALUES LESS THAN (400)
PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255
STORAGE(INITIAL 81920 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE
DEFAULT)
TABLESPACE "YANGTK" NOCOMPRESS ,
PARTITION "SYS_P98" VALUES LESS THAN (500)
PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255
STORAGE(INITIAL 81920 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFA
ULT)
TABLESPACE "YANGTK" NOCOMPRESS ,
PARTITION "SYS_P99" VALUES LESS THAN (800)
PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255
STORAGE(INITIAL 81920 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
TABLESPACE "YANGTK" NOCOMPRESS )
需要注意，INTERVAL分区在DBMS_METADATA获取的表结构中并不会出现，一旦转化为RANGE分区，则DBMS_METADATA获取的源数据会包括分区信息。
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