67 lines
1.6 KiB
Plaintext
67 lines
1.6 KiB
Plaintext
.\" This is -*-nroff-*-
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.\" XXX standard disclaimer belongs here....
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.\" $Header: /cvsroot/pgsql/src/man/Attic/fetch.l,v 1.6 1998/03/23 15:09:29 momjian Exp $
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.TH FETCH SQL 01/23/93 PostgreSQL PostgreSQL
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.SH NAME
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fetch - fetch instance(s) from a cursor
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.SH SYNOPSIS
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.nf
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\fBfetch\fR [ (\fBforward\fR | \fBbackward\fR) ] [ ( number | \fBall\fR) ] [\fBin\fR cursor_name]
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.fi
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.SH DESCRIPTION
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.BR Fetch
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allows a user to retrieve instances from a cursor named
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.IR cursor_name.
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The number of instances retrieved is specified by
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.IR number .
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If the number of instances remaining in the cursor is less than
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.IR number ,
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then only those available are fetched. Substituting the keyword
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.IR all
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in place of a number will cause all remaining instances in the cursor
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to be retrieved. Instances may be fetched in both
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.IR forward
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and
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.IR backward
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directions. The default direction is
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.IR forward .
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.PP
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Updating data in a cursor is not supported by Postgres, because mapping
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cursor updates back to base classes is impossible in general as with
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view updates. Consequently, users must issue explicit replace
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commands to update data.
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.PP
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Cursors may only be used inside of transaction blocks marked by
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.IR begin (l)
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and
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.IR commit (l)
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because the data that they store spans multiple user queries.
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.SH EXAMPLE
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.nf
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--
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--set up and use a cursor
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--
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begin work;
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declare mycursor cursor for
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select * from pg-user;
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--
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--Fetch all the instances available in the cursor FOO
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--
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fetch all in FOO;
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--
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--Fetch 5 instances backward in the cursor FOO
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--
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fetch backward 5 in FOO;
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--
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--close
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--
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close foo;
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commit;
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.fi
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.SH "SEE ALSO"
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begin(l),
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commit(l),
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close(l),
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move(l),
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select(l).
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