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<< Click to Display Table of Contents >> CREATE INDEX Command |
  
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<< Click to Display Table of Contents >> CREATE INDEX Command |
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CREATE INDEX defines a new index on an existing table.
CREATE [ UNIQUE ] INDEX index_name ON [ MEMORY ] table_name
( column_name [ ASC | DESC ] [ CASE | NOCASE ] [, ... ] )
CREATE INDEX constructs an index index_name on the specified table. Indexes are primarily used to enhance database performance (though inappropriate use will result in slower performance).
Multi-column indexes are allowed.
UNIQUE
Causes the database engine to check for duplicate values in the table when the index is created (if data already exist) and each time data is added. Attempts to insert or update data which would result in duplicate entries will generate an error.
index_name
The name of an index to be created.
MEMORY
If MEMORY keyword is specified before the table_name then an in-memory table is referenced, not a disk one.
table_name
The name of the table to be removed.
column_name
The name of a column to be indexed.
ASC
The column will be indexed with ascending sort order. This is the default.
DESC
The column will be indexed with descending sort order.
CASE
The column will be indexed with case-sensitive sort order. This is the default.
NOCASE
The column will be indexed with case-insensitive sort order.
Example:
CREATE UNIQUE INDEX idxUniqueName ON developers (name DESC NOCASE, code);
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