Shulou(Shulou.com)06/01 Report--

Concept: a structure created to speed up queries, physically and logically independent of table data

Index classification: B-tree index (unique index, combined index, reverse key index, function-based index), bitmap index

Create index: default is USERS tablespace

Analytical index: used to remove fragmentation in the index; when there are more fragments in the index, the index can be rebuilt

Unique index: there are no duplicate values on the indexed column; multiple null values can be inserted

Composite indexes: creating indexes on multiple columns

Reverse key index: reverses each byte of the key value of an index column, usually applied to a column with a continuous increase in value.

Bitmap index: applied to a low cardinality column (a limited number of values on a column)

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