Database Design

Definition

Database design is the design subactivity consisting of the cohesive collection of all tasks involving the design of one or more related databases (or datastores).

Goals

The goals of database design are to:

Produce the design of one or more related databases.
Ensure that the design fulfills the relevant requirements.
Ensure that the design conforms to the relevant architecture.

Objectives

To meet this goal, the objectives of database design are to:

Produce logical database designs.
Produce physical database designs.
Ensure that these designs are properly documented.

Examples

Examples of database design include:

Flat File Design
Hierarchical Database Design
Network Database Design
Object Database Design
Relational Database Design
XML Database Design

Preconditions

Databse design may typically begin when the following preconditions hold:

The initiation phase has started.
The database team is initially staffed and adequately trained in database design.
The following documents are largely complete and are relatively stable:
- Requirements Documents:
- Architecture Documents:

Completion Criteria

Database design is typically complete when the following postconditions hold:

The database design document:
- Is complete.
- Has passed evaluation.
- Has been accepted by the customer representative.
- Been delivered to the customer organization.

Tasks

Database design typically involves the following producers performing the following design tasks in an iterative, incremental, and parallel manner:

Database Team, which performs:
- Design Reuse
- Design Prototyping
- Design Production:
  - Logical Data Model (i.e., Logical Database Schema) Production:
    - Relational Model (e.g., entity relationship attribute (ERA) diagrams and table definitions).
    - Object Model (e.g., class diagrams, class specifications).
    - Hierarchical Model (e.g., hierarchy diagrams).
  - Physical Data Model (i.e., Physical Database Schema) Production:
    - Relational Model (e.g., entity relationship attribute (ERA) diagrams,table definitions, stored procedures, triggers).
    - Object Model (e.g., class diagrams, class specifications).
    - Hierarchical Model (e.g., hierarchy diagrams).
  - Database Facade Design using the following techniques:
    - Access Analysis
    - Data Mapping
- Design Refactoring using the following techniques:
  - Database Clustering
  - Database Fragmentation
  - Database Indexing
  - Database Normalization (and denormalization)
  - Database Tuning
  - Data Replication
- Design Documentation

Work Products

Database design results in the production of the following work products:

Documents:
- Database Design Document
- Data Dictionary
Models:
- Data Model (Relational Databases)
- Document Model (XML Databases)
- Hierarchy Model (Hierarchical Databases)
- Object Model (Object Databases)
Diagrams: