System Development Life Cycle
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Data Models

Models are a cornerstone of design. Engineers build a model of a car to work out any details before putting it into production. In the same manner, system designers develop models to explore ideas and improve the understanding of the database design.

 

Purpose of models :

Models help communicate the concepts in people’s mind. They can be used to do the following:

Communicate, categorize, describe, specify, investigate, evolve, analyze, imitate.

The objective is to produce a model that fits a multitude of these uses, can be understood by an end user, and contains sufficient detail for a developer to build a database system.

 

ER Modeling

An ER model is an illustration of various entities in a business and the relationships between them. An ER model is derived from business specifications or narratives and built during the analysis phase of the SDLC. ER models separate the information required by a business from the activities performed within a business. Although business can change their activities, the type of information thends to remain constant. Therefore, the data structures also tend to be constant.

 

Benefits of ER Modeling

1. Documents information for the organization in a clear, precise format
2. Provides a clear picture of the scope of the information requirement
3. Provides an easily understood pictorial map for the database design
4. Offers an effective framework for integrating multiple applications