Using the procedural languages v4

The Postgres procedural languages (PL/Perl, PL/Python, and PL/Tcl) are installed by the Language Pack installer. You can also use a native package to add procedural language functionality to your EDB Postgres Advanced Server installation.

PL/Perl

The PL/Perl procedural language allows you to use Perl functions in Postgres applications.

You must install PL/Perl in each database (or in a template database) before creating a PL/Perl function. Use the CREATE LANGUAGE command at the EDB-PSQL command line to install PL/Perl. Open the EDB-PSQL client, establish a connection to the database in which you wish to install PL/Perl, and enter the command:

CREATE EXTENSION plperl;

You can now use a Postgres client application to access the features of the PL/Perl language. The following PL/Perl example creates a function named perl_max that returns the larger of two integer values:

CREATE OR REPLACE FUNCTION perl_max (integer, integer) RETURNS integer AS
$$
if ($_[0] > $_[1])
{ return $_[0]; }
return $_[1];
$$ LANGUAGE plperl;

Pass two values when calling the function:

SELECT perl_max(1, 2);

The server returns:

perl_max
---------
       2
(1 row)

For more information about using the Perl procedural language, consult the official PostgreSQL documentation.

PL/Python

The PL/Python procedural language allows you to create and execute functions written in Python within Postgres applications. The version of PL/Python used by EDB Postgres Advanced Server and PostgreSQL is untrusted (plpython3u); it offers no restrictions on users to prevent potential security risks.

Install PL/Python in each database (or in a template database) before creating a PL/Python function. You can use the CREATE LANGUAGE command at the EDB-PSQL command line to install PL/Python. Use EDB-PSQL to connect to the database in which you wish to install PL/Python, and enter the command:

CREATE EXTENSION plpython3u;

After installing PL/Python in your database, you can use the features of the PL/Python language.

The following PL/Python example creates a function named pymax that returns the larger of two integer values:

CREATE OR REPLACE FUNCTION pymax (a integer, b integer) RETURNS integer AS
$$
if a > b:
return a
return b
$$ LANGUAGE plpython3u;

When calling the pymax function, pass two values as shown below:

SELECT pymax(12, 3);

The server returns:

pymax
-------
    12
(1 row)

For more information about using the Python procedural language, consult the official PostgreSQL documentation.

PL/Tcl

The PL/Tcl procedural language allows you to use Tcl/Tk functions in applications.

You must install PL/Tcl in each database (or in a template database) before creating a PL/Tcl function. Use the CREATE LANGUAGE command at the EDB-PSQL command line to install PL/Tcl. Use the psql client to connect to the database in which you wish to install PL/Tcl, and enter the command:

CREATE EXTENSION pltcl;

After creating the pltcl language, you can use the features of the PL/Tcl language from within your Postgres server.

The following PL/Tcl example creates a function named tcl_max that returns the larger of two integer values:

CREATE OR REPLACE FUNCTION tcl_max(integer, integer) RETURNS integer AS 
$$
if {[argisnull 1]} {
if {[argisnull 2]} { return_null }
return $2
}
if {[argisnull 2]} { return $1 }
if {$1 > $2} {return $1}
return $2
$$ LANGUAGE pltcl;

Pass two values when calling the function:

SELECT tcl_max(1, 2);

The server returns:

tcl_max
--------
      2
(1 row)

For more information about using the Tcl procedural language, consult the official PostgreSQL documentation.