We have multi-column indexes, so update manual.
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.\" This is -*-nroff-*-
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.\" This is -*-nroff-*-
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.\" XXX standard disclaimer belongs here....
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.\" XXX standard disclaimer belongs here....
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.\" $Header: /cvsroot/pgsql/src/man/Attic/create_index.l,v 1.6 1997/05/14 01:38:34 vadim Exp $
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.\" $Header: /cvsroot/pgsql/src/man/Attic/create_index.l,v 1.7 1997/10/30 18:41:03 momjian Exp $
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.TH "CREATE INDEX" SQL 11/05/95 PostgreSQL PostgreSQL
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.TH "CREATE INDEX" SQL 11/05/95 PostgreSQL PostgreSQL
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.SH NAME
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.SH NAME
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create index \(em construct a secondary index
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create index \(em construct a secondary index
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@ -44,14 +44,7 @@ result of a user-defined function
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.IR funcname
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.IR funcname
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applied to one or more attributes of a single class. These
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applied to one or more attributes of a single class. These
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.IR "functional indices"
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.IR "functional indices"
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are primarily useful in two situations. First, functional indices can
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can be used to obtain fast access to data based on
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be used to simulate multi-key indices. That is, the user can define a
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new base type (a simple combination of, say, \*(lqoid\*(rq and
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\*(lqint2\*(rq) and the associated functions and operators on this new
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type such that the access method can use it. Once this has been done,
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the standard techniques for interfacing new types to access methods
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(described in the Postgres user manual) can be applied. Second,
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functional indices can be used to obtain fast access to data based on
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operators that would normally require some transformation to be
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operators that would normally require some transformation to be
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applied to the base data. For example, say you have an attribute in
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applied to the base data. For example, say you have an attribute in
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class \*(lqmyclass\*(rq called \*(lqpt\*(rq that consists of a 2D
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class \*(lqmyclass\*(rq called \*(lqpt\*(rq that consists of a 2D
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