Database Architecture

 Database Architecture

Database Architecture refers to the design and structure of a database system that defines how data is stored, managed, and accessed. It explains the interaction between users, applications, and the database management system (DBMS).

Database architecture is mainly divided into three levels, known as the Three-Schema Architecture:

🔹 1️⃣ External Level (View Level)

  • The highest level of abstraction

  • Describes how individual users view the data

  • Different users can have different views of the same database

🔹 2️⃣ Conceptual Level (Logical Level)

  • Describes the overall logical structure of the database

  • Includes tables, relationships, constraints, and data types

  • Independent of physical storage details

🔹 3️⃣ Internal Level (Physical Level)

  • The lowest level of abstraction

  • Describes how data is physically stored in files

  • Includes indexing, file organization, and storage structures

🔹 Types of Database Architecture (Based on Deployment)

  • 1-Tier Architecture – User directly interacts with the database (used for local applications).

  • 2-Tier Architecture – Client communicates directly with the database server.

  • 3-Tier Architecture – Includes presentation layer, application layer, and database layer (commonly used in web applications).

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