Databases Reference
In-Depth Information
7.2
List Partitioning
7.2.1 Essentials of List Partitioning
Although users normally think of range partitioning as a technique that groups a range
of data together, such as a range of dates or a range of numbers, the same technique can
be used to group point values, such as regions (e.g., New York, Ohio, Florida). A single
value or a set of distinct values can form the “range.” Some vendors refer to this as
list
partitioning
(e.g., Oracle), because each range of data is defined by a list of one or more
values. Other vendors don't bother with the distinctions, and simply include this capa-
bility as part of their range partitioning abilities (e.g., IDS, DB2).
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Figure 7.2
Composite range and list partitioning. (Picture courtesy of Oracle Corp.)
7.2.2 Composite Range and List Partitioning
List partitioning can be combined with normal range partitioning to produce a grid of
multi-attribute nonoverlapping ranges.
The following section, “Syntax Examples,” illustrates a typical combination of
range and list partitioning over both date and geographies.
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List partitioning was introduced in Oracle in Oracle 9i, and in DB2 9 as part of its partitioned
tables capability. Informix IDS has supported this concept for several releases as part of its Frag-
ment clause.
