PostgreSQL Interview Preparation Guide
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PostgreSQL Interview Questions and Answers will guide us about PostgreSQL, often simply Postgres, is an object-relational database management system (ORDBMS). It is released under a MIT-style license and is thus free and open source software. As with many other open source programs, PostgreSQL is not controlled by any single company, but has a global community of developers and companies to develop it. Learn PostgreSQL by this PostgreSQL Interview Questions with Answers guide

24 PostgreSQL Questions and Answers:

1 :: Explain what is PostgreSQL?

This is regarded as one of the most successful open source database in the world. This is also used to create advanced applications. This relies on Object relational database management system. Familiarity with UNIX and Linux can be an added advantage while using PostgreSQL.

2 :: State some of the advanced features of PostgreSQL?

These are the following features which are present in PostgreSQL they are
1) Object relational database
2) Extensibility and support for SQL
3) Database validation and flexible API
4) Procedural languages and MVCC
5) Client server and WAL.

3 :: Explain about Write Ahead logging?

This feature increases the reliability of the database by logging changes before any changes or updations to the data base. This provides log of database incase of a database crash. This helps to start the work from the point it was discontinued.

4 :: Explain about Multi version concurrency control?

Multi version concurrency control or MVCC is used to avoid unnecessary locking of the database. This removes the time lag for the user to log into his database. This feature or time lag occurs when some one else is on the content. All the transactions are kept as a record.

5 :: How to start the database server?

/usr/local/etc/rc.d/ start
/usr/local/etc/rc.d/postgresql start

6 :: How to stop the database server?

/usr/local/etc/rc.d/ stop
/usr/local/etc/rc.d/postgresql stop

7 :: How to check whether PostgreSQL server is up and running?

/usr/local/etc/rc.d/ status
/usr/local/etc/rc.d/postgresql status?

8 :: What are the languages which PostgreSQL supports?

Some of the languages which PostgreSQL supports are as follows: -
It supports a language of its own known as PL/pgSQL and it supports internal procedural languages. Pl/pgSQL can be compared to oracle, PL/SQL, etc. Languages such as Perl, Python, TCL can be used as embedded languages.

9 :: Explain about the command enable debug?

This command is used for enabling compilation of all libraries and applications. This process generally slows down the system and it also increases the binary file size. Debugging symbols are present which can assist developers in noticing bugs and problems associated with their script.

10 :: Explain about functions in PostgreSQL?

Functions are important because they help the code to be executed on the server. Some of the languages which can program functions for efficient use are PL/pgSQL which is the native language of PostgreSQL. Scripting languages are supported by many languages such as PHP, Perl, Python, etc. PL/R a statistical language can also be used.