Table 3-1 summarizes the types of partitioned indexes that Oracle supports. The key points are:
If an index is local, then it is equipartitioned with the underlying table. Otherwise, it is global.
A prefixed index is partitioned on a left prefix of the index columns. Otherwise, it is nonprefixed.
Table 3-1 Types of Partitioned Indexes
| Type of Index | Index Equipartitioned with Table | Index Partitioned on Left Prefix of Index Columns | UNIQUE Attribute Allowed | Example: Table Partitioning Key | Example: Index Columns | Example: Index Partitioning Key |
|---|---|---|---|---|---|---|
|
Local Prefixed (any partitioning method) |
Yes |
Yes |
Yes |
A |
A, B |
A |
|
Local Nonprefixed (any partitioning method) |
Yes |
No |
Yes1 |
A |
B, A |
A |
|
Global Prefixed (range partitioning only) |
No2 |
Yes |
Yes |
A |
B |
B |
For a unique local nonprefixed index, the partitioning key must be a subset of the index key and cannot be a partial index.
Although a global partitioned index may be equipartitioned with the underlying table, Oracle does not take advantage of the partitioning or maintain equipartitioning after partition maintenance operations such as DROP or SPLIT PARTITION.