8 Part 8: Annex

8.1 Method References

8.1.3 Database Modeling

Usage

Preparing Database Design

Reference

KE04

Purpose

• the representation of entity types, relation types and cardinalities with accordingly different graphical symbols, and
• the indication of the names of all entity types and relation types in the diagram.

Database modeling consists of several submethods: ER Modeling In Entity Relationship Modeling („ER Modeling“) within the scope of a specified terms of reference a »Data Model is prepared that is based in general only on technical factors and the view of the users and not on the realization of the IT system. The aim of ER Modeling is to describe the objects that are represented by data in an information processing system and their mutual relations. The ER Model is prepared in a top-down approach where in each design step more detailed and refined structures emerge. For the description of ER Modeling, the ER diagram is used. An ER diagram mainly consists of the following

Data Navigation Modeling

The method "Data Navigation Modeling" is used to generate a database-management-oriented (DBMS) data structure from an entity-relationship-model (ER Model). Data Navigation Modeling is helpful in particular for the generation of powerful hierarchical and network-like database structures.

Normalization

The aim of "normalization" is the formation of data structures (entity types with attributes) so that specific regularities, so-called normalization rules, are observed, which have, among other things, the following effects:

• Elimination of redundancies,
• Elimination of anomalies that may occur when inserting, deleting or modifying data in data structures.