Three-level Data Modeling in Databases Design

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Three-level Data Modeling in Databases Design

Three-level data modeling is a framework used in database design to separate the different levels of abstraction in data representation. It consists of three levels: the conceptual level, the logical level, and the physical level.

The data modeling process typically follows these steps:

  1. Conceptual Level
  2. Logical Level
  3. Physical Level

Conceptual Level

  • Represents high-level business requirements and entities without implementation details
  • Uses Entity-Relationship (ER) diagrams to model relationships between business concepts
  • Independent of any specific database technology or implementation approach (e.g., relational, hierarchical, network, etc.) and DBMS(Database Management System)-independent (e.g., Oracle, MySQL, PostgreSQL, etc.)

Logical Level

  • Defines tables, columns, primary keys, foreign keys, and relationships in a structured format
  • Based on a specific data model (e.g., relational model) but remains DBMS-independent
  • Includes normalization rules and data integrity constraints

Note: Nowadays, the relational model or NoSQL is predominantly used.

Physical Level

  • Specifies actual implementation details for a particular DBMS (e.g., PostgreSQL, MySQL)
  • Includes indexes, partitions, storage parameters, and performance optimization settings
  • Contains file organization, data types, and physical storage structures