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1 | 1 | .\" This is -*-nroff-*- |
2 | 2 | .\" XXX standard disclaimer belongs here.... |
3 | | -.\" $Header: /cvsroot/pgsql/src/man/Attic/create_index.l,v 1.6 1997/05/14 01:38:34 vadim Exp $ |
| 3 | +.\" $Header: /cvsroot/pgsql/src/man/Attic/create_index.l,v 1.7 1997/10/30 18:41:03 momjian Exp $ |
4 | 4 | .TH "CREATE INDEX" SQL 11/05/95 PostgreSQL PostgreSQL |
5 | 5 | .SH NAME |
6 | 6 | create index\(em construct a secondary index |
@@ -44,14 +44,7 @@ result of a user-defined function |
44 | 44 | .IR funcname |
45 | 45 | applied to one or more attributes of a single class. These |
46 | 46 | .IR"functional indices" |
47 | | -are primarily useful in two situations. First, functional indices can |
48 | | -be used to simulate multi-key indices. That is, the user can define a |
49 | | -new base type (a simple combination of, say,\*(lqoid\*(rq and |
50 | | -\*(lqint2\*(rq) and the associated functions and operators on this new |
51 | | -type such that the access method can use it. Once this has been done, |
52 | | -the standard techniques for interfacing new types to access methods |
53 | | -(described in the Postgres user manual) can be applied. Second, |
54 | | -functional indices can be used to obtain fast access to data based on |
| 47 | +can be used to obtain fast access to data based on |
55 | 48 | operators that would normally require some transformation to be |
56 | 49 | applied to the base data. For example, say you have an attribute in |
57 | 50 | class\*(lqmyclass\*(rq called\*(lqpt\*(rq that consists of a 2D |
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