dblink

Description

executes a query (usually aSELECT, but it can be any SQL statement that returns rows) in a remote database.

When twotextarguments are given, the first one is first looked up as a persistent connection’s name; if found, the command is executed on that connection. If not found, the first argument is treated as a connection info string as fordblink_connect, and the indicated connection is made just for the duration of this command.

connname

connstr

A connection info string, as previously described for.

sql

fail_on_error

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 returns no rows.

Return Value

The function returns the row(s) produced by the query. Sincedblinkcan be used with any query, it is declared to returnrecord, rather than specifying any particular set of columns. This means that you must specify the expected set of columns in the calling query — otherwisePostgreSQLwould not know what to expect. Here is an example:

A convenient way to usedblinkwith predetermined queries is to create a view. This allows the column type information to be buried in the view, instead of having to spell it out in every query. For example,

Examples