Database System Concepts and Architecture

•Provide concepts that are close to the way many users perceive data.

• •Implementation (representational) data models

• •Physical (low-level, internal) data models

• •Conceptual (high-level, semantic) data models

• •Self-Describing Data Models

Three-Schema Architecture :

• External schemas

• Internal schema

• Schema Construct

• Conceptual schema

Categories of Data Models:

• •File server

• •Implementation (representational) data models.

• •High Level or Non-procedural Language

• •Low Level or Procedural Language.

•These must be embedded in a programming language

•A state that satisfies the structure and constraints of the database.

• Distinction

• Initial Database State

• Valid State

• Database Schema

Types of DML :

• Data Manipulation Language

• Data Definition Language

• High Level or Non-procedural Language

• Low Level or procedural Language

applied to individual database components

• instance

• Schema Diagram

• Data Model

• Distinction

Operations on the data model may include :

• Client-Server Architectures

• basic model operations

• Self-Describing Data Models

• user-defined operations

Centralized DBMS :

Combines everything into single system including :

• DBMS software

• hardware

• application programs

• All

Clients can access the specialized servers as ....