ALTER command to add and drop Mysql Index
by Rekha[ Edit ] 2010-09-23 15:51:30
ALTER command to add and drop Mysql Index
There are four types of statements for adding indexes to a table:
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ALTER TABLE tbl_name ADD PRIMARY KEY (column_list) : This statement adds a PRIMARY KEY, which means that indexed values must be unique and cannot be NULL.
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ALTER TABLE tbl_name ADD UNIQUE index_name (column_list): This statement creates an index for which values must be unique (with the exception of NULL values, which may appear multiple times).
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ALTER TABLE tbl_name ADD INDEX index_name (column_list): This adds an ordinary index in which any value may appear more than once.
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ALTER TABLE tbl_name ADD FULLTEXT index_name (column_list): This creates a special FULLTEXT index that is used for text-searching purposes.
