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'\" t
.\" Title: dblink_open
.\" Author: The PostgreSQL Global Development Group
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\" Date: 2024
.\" Manual: PostgreSQL 16.2 Documentation
.\" Source: PostgreSQL 16.2
.\" Language: English
.\"
.TH "DBLINK_OPEN" "3" "2024" "PostgreSQL 16.2" "PostgreSQL 16.2 Documentation"
.\" -----------------------------------------------------------------
.\" * Define some portability stuff
.\" -----------------------------------------------------------------
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.\" http://bugs.debian.org/507673
.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.ie \n(.g .ds Aq \(aq
.el .ds Aq '
.\" -----------------------------------------------------------------
.\" * set default formatting
.\" -----------------------------------------------------------------
.\" disable hyphenation
.nh
.\" disable justification (adjust text to left margin only)
.ad l
.\" -----------------------------------------------------------------
.\" * MAIN CONTENT STARTS HERE *
.\" -----------------------------------------------------------------
.SH "NAME"
dblink_open \- opens a cursor in a remote database
.SH "SYNOPSIS"
.sp
.nf
dblink_open(text cursorname, text sql [, bool fail_on_error]) returns text
dblink_open(text connname, text cursorname, text sql [, bool fail_on_error]) returns text
.fi
.SH "DESCRIPTION"
.PP
\fBdblink_open()\fR
opens a cursor in a remote database\&. The cursor can subsequently be manipulated with
\fBdblink_fetch()\fR
and
\fBdblink_close()\fR\&.
.SH "ARGUMENTS"
.PP
\fIconnname\fR
.RS 4
Name of the connection to use; omit this parameter to use the unnamed connection\&.
.RE
.PP
\fIcursorname\fR
.RS 4
The name to assign to this cursor\&.
.RE
.PP
\fIsql\fR
.RS 4
The
\fBSELECT\fR
statement that you wish to execute in the remote database, for example
select * from pg_class\&.
.RE
.PP
\fIfail_on_error\fR
.RS 4
If true (the default when omitted) then an error thrown on the remote side of the connection causes an error to also be thrown locally\&. If false, the remote error is locally reported as a NOTICE, and the function\*(Aqs return value is set to
ERROR\&.
.RE
.SH "RETURN VALUE"
.PP
Returns status, either
OK
or
ERROR\&.
.SH "NOTES"
.PP
Since a cursor can only persist within a transaction,
\fBdblink_open\fR
starts an explicit transaction block (\fBBEGIN\fR) on the remote side, if the remote side was not already within a transaction\&. This transaction will be closed again when the matching
\fBdblink_close\fR
is executed\&. Note that if you use
\fBdblink_exec\fR
to change data between
\fBdblink_open\fR
and
\fBdblink_close\fR, and then an error occurs or you use
\fBdblink_disconnect\fR
before
\fBdblink_close\fR, your change
\fIwill be lost\fR
because the transaction will be aborted\&.
.SH "EXAMPLES"
.sp
.if n \{\
.RS 4
.\}
.nf
SELECT dblink_connect(\*(Aqdbname=postgres options=\-csearch_path=\*(Aq);
dblink_connect
\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-
OK
(1 row)
SELECT dblink_open(\*(Aqfoo\*(Aq, \*(Aqselect proname, prosrc from pg_proc\*(Aq);
dblink_open
\-\-\-\-\-\-\-\-\-\-\-\-\-
OK
(1 row)
.fi
.if n \{\
.RE
.\}
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