open/execute huge sql file
PostgreSQL database dumps are normally produced by the command line tool pg_dump, and expected to be used via either pg_restore or simply psql command line tools.

However, you can both backup and restore from PgAdminIII. The backup option is available via right-clicking either the server or any database or schema. The Restore option is available via right-clicking a database or schema.

Here's a step-by-step example of how dump or restore a database using PgAdmin.