How can I import a partition from one table into another in Oracle?
I would like to know if the following steps are possible and how fast this is:
- Create a partition named part1 in Table A
- Drop partition part1 in Table B
- Impo开发者_开发知识库rt the Table A partition part1 into Table B
Can you provide me with an example if it is possible indeed? Or any resources I can look at?
Note that the tables would have the exact same structure.
You can do something similar with the ALTER TABLE ... EXCHANGE PARTITION
command. This would exchange a single partition with a table that has the same structure.
A little example:
/* Partitionned Table Creation */
SQL> CREATE TABLE table_a (
2 ID NUMBER PRIMARY KEY,
3 DATA VARCHAR2(200)
4 )
5 PARTITION BY RANGE (ID) (
6 PARTITION part100 VALUES LESS THAN (100),
7 PARTITION part200 VALUES LESS THAN (200)
8 );
Table created
/* Swap table creation */
SQL> CREATE TABLE swap_table (
2 ID NUMBER PRIMARY KEY,
3 DATA VARCHAR2(200)
4 );
Table created
SQL> INSERT INTO swap_table SELECT ROWNUM, 'a' FROM dual CONNECT BY LEVEL <= 99;
99 rows inserted
SQL> select count(*) from table_a partition (part100);
COUNT(*)
----------
0
This will exchange the partition part100
with the transition table swap_table
:
SQL> ALTER TABLE table_a EXCHANGE PARTITION part100 WITH TABLE swap_table;
Table altered
SQL> select count(*) from table_a partition (part100);
COUNT(*)
----------
99
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