PostgreSQL,or Postgres, is an object-relational database management system (ORDBMS) with an emphasis on extensibility and on standards-compliance.
Postgres is currently available from slackbuilds.org and can be installed via that.
The official PHP Slackware package currently does not ship with Postgres support. To enable it the source and SlackBuild script for the PHP package should be downloaded from a Slackware mirror and the following configure options should be added to php.SlackBuild before building:
--with-pdo-pgsql=shared --with-pgsql=shared
php-pgsql could be installed via SBo
After installing the required modules can be enabled via php.ini