Database
A database is an organized collection of data that can be easily accessed, managed, and updated. Databases are essential for storing information in applications, websites, and systems of all sizes.
🧩 Types of Databases
- Relational Databases (SQL): Store data in tables with rows and columns. Use Structured Query Language (SQL) for queries.
- Examples: MySQL, PostgreSQL, SQLite, Oracle, Microsoft SQL Server
- NoSQL Databases: Designed for flexible, scalable storage of unstructured or semi-structured data.
- Types: Document (MongoDB), Key-Value (Redis), Column (Cassandra), Graph (Neo4j)
- In-Memory Databases: Store data in RAM for fast access.
- Examples: Redis, Memcached
- Time Series Databases: Optimized for time-stamped data.
- Examples: InfluxDB, TimescaleDB
🏆 Why Use a Database?
- Efficiently store and retrieve large amounts of data
- Ensure data consistency, integrity, and security
- Support concurrent access by multiple users
- Enable backup, recovery, and data management
🛠️ Key Concepts
- Table: Structure for organizing data in rows and columns (relational).
- Record/Row: A single entry in a table.
- Field/Column: An attribute or property of the data.
- Primary Key: Unique identifier for a record.
- Index: Improves the speed of data retrieval.
- Query: Request for data or information from the database.
- Transaction: A sequence of operations performed as a single unit.
📚 Resources
📝 Notes
- Choose the right database type based on your application's needs (structure, scale, speed).
- Regularly back up your databases to prevent data loss.
- Understand ACID properties (Atomicity, Consistency, Isolation, Durability) for reliable transactions in relational databases.