Extract From PostgreSQL Database

Introducing PostgreSQL

Another common relational database used by the industry is PostgreSQL. PostgreSQL is open-sourced and has been around since 1996 so it’s a stable database with great support and community. It’s used primarily as a database for web and analytics applications.

While MySQL is a simple and fast OLTP database, PostgreSQL is a feature-rich database that can handle complex analytical queries and can be used for both OLTP and OLAP use cases.

One of the main advantages of PostgreSQL over MySQL is that PostgreSQL offers support for multiple programming languages, most notably PL/pgSQL.

PL/pgSQL is a procedural programming language for the PostgreSQL database system. It allows users to extend the functionality of PostgreSQL by adding complex logic, for example, control structures such as if, case, for, and while loop statements and more.

Many large organizations use PostgreSQL. Some examples are:

• Uber

• Netflix

• Instagram

• Spotify

• Instacart

• LaunchDarkly

• Robinhood

• Reddit

Extracting data from PostgreSQL

We can easily extract data from a PostgreSQL database using Python's library called psycopg2.

psycopg2 is a PostgreSQL driver that allows us to connect to and query a PostgreSQL database using Python.

First, we need to acquire the connection details of an active PostgreSQL database, the connection details are:

• host

• port

• user

• password

• database

Next, we use Python to perform queries on the database. For example, let's extract the top two highest-paid employees in the company and export the data as CSV. The employees' details are stored in the following table: