CS-GY 6083: Principles of Database Systems
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main
  • Introduction
  • DBMS Basics
    • Introduction to DBMS
    • Why use a DBMS instead of a File System?
    • Levels of Abstraction
    • Instances and Schemas
  • Data Models
    • Introduction to Data Models
    • Database Languages
    • Database Design
  • DBMS Internals
    • Introduction to DBMS Internals
    • Storage Manager
    • Query Processor
    • Transaction Management
    • Database Users
    • Database Architecture
  • DBMS History
  • Some Popular Database Systems
  • OLTP, OLAP, and Data Mining
  • Databases vs. Information Retrieval
  • The Entity-Relationship Model - Details
    • Introduction
    • Cardinality Constraints
    • ER Diagram Components
    • ER Diagram to Relational Schema
    • Design Issues
  • The Relational Model - Details
    • Relations
    • Keys
    • Relational Query Languages
      • Relational Algebra
      • Relational Calculus
      • Relative Expressive Power
    • Relational Operators
  • SQL
    • Introduction to SQL
    • Domain Types in SQL
    • DDL Commands
      • Creating a Table
      • Alter and Drop
    • DML Commands
      • Basic Query Structure
      • Select
      • From
      • Where
      • Joins
      • Rename
      • String Operations
      • Ordering
      • Set Operations
      • Group By and Having
      • Nested Subqueries
      • Test for Empty Relations
      • Test for Duplicate Tuples
      • Derived Relations
      • With
      • Database Modification
    • Intermediate SQL
      • Joins Revisited
      • Views
      • Transactions
      • Integrity Constraints
      • More SQL Data Types and Schemas
        • Other Features
      • Authorization
    • Advanced SQL
      • Accessing SQL From a Programming Language
        • ODBC and JDBC
        • Embedded SQL
        • PHP
        • Some Security Issues
      • Accessing Metadata
      • Text Operations
        • Like
        • Contains
      • Cursors
      • Functions and Procedures
        • Procedural Constructs
        • External Language Routines
      • Triggers
      • Ranking
      • Windowing
      • OLAP
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  • Relational Model
  • ER (Entity-Relationship) Model
  • Object-Based Data Model
  • Semi-Structured Data Model

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  1. Data Models

Introduction to Data Models

PreviousData ModelsNextDatabase Languages

Last updated 4 years ago

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A data model is a collection of tools for describing data and the associated relationships, semantics and constraints.

There are several kinds of data models:

  • Relational Model

  • ER (Entity-Relationship) Model

  • Object-Based Data Models (Object-Oriented and Object-Relational)

  • Semi-Structured Data Models

  • Other Models (Network Model, Hierarchical Model etc.)

Relational Model

This model assumes each table to be a relation.

The attributes/relation names are represented as columns of the table and the values for the relations are represented in the rows of the table.

The Relational Model is discussed in detail in later chapters.

ER (Entity-Relationship) Model

This model describes a set of entities and the relationships between them. It is mainly used for database design.

Object-Based Data Model

It is an extension of the relational data model. It includes object orientation and constructs to support additional data types.

Semi-Structured Data Model

It was created to represent data where data items of the same type may have different attributes. It can represent the information of some data sources that cannot be constrained by schema.

Semi-structured data model uses XML (Extensible Markup Language).