PostgeSQL/PostGIS is an open source object relational database which I am using to for my GIS projects....
The PostGIS adds support for geographic objects to the PostSQL database

Importing shape files into PostGIS

1. Use shp2pgsl utlity to convert shape file to ready to import SQL script
Basic format: shp2pgsql -W UTF-8 <file_name.shp> <schema>.<table_name> > <filename.sql>
e.g. shp2pgsql -d south_africa_administrative.shp south_africa > south_africa.sql

2. Import converted file into PostGIS
Basic format: psql -h <host_name> -U <user_name> -d <db_name> -f <file_name.sql>
e.g. psql -h localhost -U joepublic -d db_name -f siuth_africa.sql