What database management systems are you familiar with and which ones have you already worked with?

Database management systems (DBMS) come in various types, the most well-known of which are:

• Relational DBMS (SQL): MySQL, PostgreSQL, Microsoft SQL Server, Oracle Database
• Document-oriented NoSQL DBMS: MongoDB, CouchDB
• Key-value: Redis, Riak
• Column-oriented: Cassandra, HBase
• Graph: Neo4j

In my practice, I have worked with MySQL and PostgreSQL for storing structured data, used MongoDB for flexible document storage, and Redis for caching and quick data access.

Each DBMS is chosen depending on the project requirements, data volume, and query nature.