Description:

Postgresql includes the programs needed to create and run a PostgreSQL
server, which will in turn allow you to create and maintain PostgreSQL
databases. PostgreSQL is an advanced Object-Relational database
management system (DBMS) that supports almost all SQL constructs
(including transactions, subselects and user-defined types and
functions).

You should install postgresql if you want to create and maintain your
own PostgreSQL databases and/or your own PostgreSQL server. If you
are installing postgresql, you should also install postgresql-data,
which will help you get started with PostgreSQL.