Apress.Expert.Oracle.Database.Architecture.9i.and.10g.Programming.Techniques.and.Solutions.Sep.2005

CHAPTER 13 ■ PARTITIONING 579
14 PARTITION part_2
15 VALUES LESS THAN(to_date('01/01/2006','dd/mm/yyyy'))
16 (subpartition part_2_sub_1 values ( 1, 3 ),
17 subpartition part_2_sub_2 values ( 5, 7 ),
18 subpartition part_2_sub_3 values ( 2, 4, 6, 8 )
19 )
20 )
21 /
Table created.
Here you end up with five partitions altogether: two subpartitions for partition PART_1 and
three for partition PART_2.
Row Movement
You might wonder what would happen if the column used to determine the partition is modified
in any of the preceding partitioning schemes. There are two cases to consider:
• The modification would not cause a different partition to be used; the row would still
belong in this partition. This is supported in all cases.
• The modification would cause the row to move across partitions. This is supported if
row movement is enabled for the table; otherwise, an error will be raised.
We can observe these behaviors easily. In the previous example, we inserted a pair of rows
into PART_1 of the RANGE_EXAMPLE table:
ops$tkyte@ORA10G> insert into range_example
2 ( range_key_column, data )
3 values
4 ( to_date( '15-dec-2004 00:00:00',
5 'dd-mon-yyyy hh24:mi:ss' ),
6 'application data...' );
1 row created.
ops$tkyte@ORA10G> insert into range_example
2 ( range_key_column, data )
3 values
4 ( to_date( '01-jan-2005 00:00:00',
5 'dd-mon-yyyy hh24:mi:ss' )-1/24/60/60,
6 'application data...' );
1 row created.
ops$tkyte@ORA10G> select * from range_example partition(part_1);
RANGE_KEY DATA
--------- --------------------
15-DEC-04 application data...
31-DEC-04 application data...