Databases are systems that store, manage, and retrieve data efficiently. There are several types of databases, each suited to different use cases:
1. Relational Databases (RDBMS): Use structured tables to store data with relationships between them. Examples include MySQL, PostgreSQL, and Oracle. They use SQL for querying data.
2. NoSQL Databases: Designed for unstructured or semi-structured data, NoSQL databases are flexible and scalable. Types include:
– Document Databases (e.g., MongoDB)
– Key-Value Stores (e.g., Redis)
– Column-Family Stores (e.g., Cassandra)
– Graph Databases (e.g., Neo4j)
3. In-Memory Databases: Store data in RAM for faster access. Examples include Redis and Memcached.
4. Time-Series Databases: Optimized for time-stamped data, like IoT or financial data. Examples include InfluxDB and TimescaleDB.
5. Object-Oriented Databases: Store data in the form of objects, similar to object-oriented programming. Examples include db4o and ObjectDB.
6. NewSQL Databases: Combine the benefits of SQL and NoSQL, providing scalability and ACID compliance. Examples include CockroachDB and VoltDB.
Each type serves different needs, from structured data management to handling large-scale, complex, or real-time data.