![]() ![]() I advise you to find out more about the Entity-Relationship Model (A.K.A. Will only slow you down during this phase of development. ![]() You forget completely what are tables and foreign keys. During the development of the Conceptual Model, it is crucial that.Your Descriptive Model should not contain unnecessary There is no need to describe things that are not The context should be given only for what should be persisted (in aĭatabase).That's where you will have the context of everything. Model, called Descriptive Model (this is not official by Peter Chen). This document may even be a new phase, prior to the Conceptual It is here that you will generate/start a Conceptual Even before the existence of the Conceptual Model, we have toĭescribe the problem (the needs of business rules) on a paper (or aĭocument).With this technique, you can create a Model (3 actually) expressing business rules needed in a system/web application. You can see the Entity-Relationship Diagram as a tool or technique that helps you to develop a strong and concise database structure. You make a model and need to follow rules to break it down so that you pass to the next stage. The decomposition process follows strict rules proposed by Peter Chen. The Logical Model is also subsequently decomposed, resulting in the Physical Model, a final representation of the structures of the tables of a database containing the field names, their data types, relationships between tables, primary keys, foreign keys, and so on. Once ready, the model is decomposed to become a new model called the Logical Model. As you get a description of the problem/situation, you begin to develop the Conceptual Model of it. They (the models) represent stages in the course of a problem/situation. Both models are part of the whole concept of data modeling by Peter Chen, the Entity-Relationship Diagram. The second image is a Physical Model of a problem/situation. The first image shown represents a Conceptual Model of a due problem/situation. This technique (as mentioned in other answers) was developed by an American (?) named Peter Chen and it is widely used today for the development of database structures such as tables and present relations between them. ![]() I dont know the similarities and difference between bothĬan u please help me to understand in detail and to move further.īy developing databases, a DBA (or someone else) can use a Data Modeling technique known as Entity-Relationship Diagram. Then i browsed in Google images as ER Diagram i got both types of ![]()
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