What is a Database?
A database is an organized collection of data that is stored, managed, and accessed electronically. It enables users to efficiently store, retrieve, modify, and manage data in a structured way.
Types of Databases:
- Relational Database (RDBMS): Uses tables to store data with relationships between them (e.g., MySQL, PostgreSQL, Oracle).
- NoSQL Database: Designed for unstructured or semi-structured data, offering flexibility (e.g., MongoDB, Cassandra).
- Cloud Database: Hosted on cloud platforms for scalability and remote access (e.g., AWS RDS, Google Cloud Firestore).
- Distributed Database: Data is spread across multiple locations to enhance availability and performance.
- Graph Database: Stores data in graph structures for relationship-based queries (e.g., Neo4j).
- Time-Series Database: Optimized for time-stamped data like logs and sensor data (e.g., InfluxDB).
Key Components of a Database:
- Tables: Structure that stores data in rows and columns (in relational databases).
- Schema: Defines the structure, relationships, and constraints of the data.
- Indexes: Speed up search operations.
- Queries: Requests to retrieve or modify data using languages like SQL.
- Transactions: Ensure data consistency and integrity.
Database Management System (DBMS):
A DBMS is software that allows users to interact with a database. Examples include:
- SQL-based DBMS: MySQL, SQL Server, PostgreSQL
- NoSQL-based DBMS: MongoDB, Redis