[sql] Transfer data between databases with PostgreSQL

Actually, there is some possibility to send a table data from one PostgreSQL database to another. I use the procedural language plperlu (unsafe Perl procedural language) for it.

Description (all was done on a Linux server):

  1. Create plperlu language in your database A

  2. Then PostgreSQL can join some Perl modules through series of the following commands at the end of postgresql.conf for the database A:

    plperl.on_init='use DBI;'
    plperl.on_init='use DBD::Pg;'
    
  3. You build a function in A like this:

    CREATE OR REPLACE FUNCTION send_data( VARCHAR )
    RETURNS character varying AS
    $BODY$
    my $command = $_[0] || die 'No SQL command!';
    my $connection_string =
    "dbi:Pg:dbname=your_dbase;host=192.168.1.2;port=5432;";
    $dbh = DBI->connect($connection_string,'user','pass',
    {AutoCommit=>0,RaiseError=>1,PrintError=>1,pg_enable_utf8=>1,}
    );
    my $sql = $dbh-> prepare( $command );
    eval { $sql-> execute() };
    my $error = $dbh-> state;
    $sql-> finish;
    if ( $error ) { $dbh-> rollback() } else {  $dbh-> commit() }
    $dbh-> disconnect();
    $BODY$
    LANGUAGE plperlu VOLATILE;
    

And then you can call the function inside database A:

SELECT send_data( 'INSERT INTO jm (jm) VALUES (''zzzzzz'')' );

And the value "zzzzzz" will be added into table "jm" in database B.