3. Inheritance:

PostgreSQL  implements inheritance between tables in the following way.

create table logs_q1 (check (created_at >= date '2014-01-01' 
and created_at <= date '2014-03-31')) inherits (logs);

where logs in the parent table and logs_q1 is the child table.

4. Everything is Object in PostgreSQL, your table is identified by OID(Object ID), your user, tablespace, schema, everything is Object here.

Hence your PostgreSQL is considered as ODBMS.

PostgreSQL is open source database management system

Open-source software is a great way to learn.

• You can learn about programming.
• You can learn about design. You can learn
• about debugging.

PostgreSQL is Open source ORDBMS – An international team of developers maintains PostgreSQL. Team members come and go, but the core members have been enhancing PostgreSQL’s per formance and feature set since at least 1996. One advantage to PostgreSQL’s open-source nature is that talent and knowledge can be recruited as needed. The fact that this team is internat ional ensures that PostgreSQL is a product that can be used product ively in any natural language, not just English.

No License and a Large Community:

The PostgreSQL Global Development Group remains committed to making PostgreSQL available as free and open source software in perpetuity.PostgreSQL has a wide variety of community and commercial support options available for users, including:

1. Community support
2. Commercial support is also available from one of the many companies providing professional services.

Some of the commercial support vendors are.

1. Severalnines
2. 2ndQuadrant
3. EDB

Further reading: https://www.postgresql.org/support/professional_support/northamerica/