'\" t
.\"     Title: dblink_open
.\"    Author: The PostgreSQL Global Development Group
.\" Generator: DocBook XSL Stylesheets v1.75.2 <http://docbook.sf.net/>
.\"      Date: 2016
.\"    Manual: PostgreSQL 9.5.2 Documentation
.\"    Source: PostgreSQL 9.5.2
.\"  Language: English
.\"
.TH "DBLINK_OPEN" "3" "2016" "PostgreSQL 9.5.2" "PostgreSQL 9.5.2 Documentation"
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.nh
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.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\(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
.\}