Introduction to Index Segments (24)

Every nonpartitioned index in an Oracle database has a single index segment to hold
all of its data. For a partitioned index, every partition has a single index segment to
hold its data.
Oracle creates the index segment for an index or an index partition when you issue the
CREATE INDEX statement. In this statement, you can specify storage parameters for
the extents of the index segment and a tablespace in which to create the index
segment. (The segments of a table and an index associated with it do not have to
occupy the same tablespace.) Setting the storage parameters directly affects the
efficiency of data retrieval and storage.

1. 非分区索引,有单独的索引段
2. 分区索引,有单独的索引段
3. 使用CREATE INDEX时,创建索引段
4. 使用CREATE INDEX时,可以指定其存储参数 , 这些参数直接影响数据提取和存储的效率
5. 表和索引可以不在(最好不在)同一个表空间中

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