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Go Back  dBforums > General > Database Concepts & Design > When should UML instead of ERM be used as modeling language in the field of DBS?

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Old 01-08-05, 08:50
weiss_adler weiss_adler is offline
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Question When should UML instead of ERM be used as modeling language in the field of DBS?

A little bit tricky. Anyone knows the answer?
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Old 01-08-05, 13:27
andrewst andrewst is offline
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When your client/boss says "this must be done in UML"
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Old 01-08-05, 13:50
Vmusic Vmusic is offline
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Unified (Yeah right) Modeling Language

Hi,
UML is really touted as a complete methodology that encompasses more than just design. It is a 'collection' of processess and artifacts.

In the space of 'data' - UML would use class diagrams. Class diagrams focus in on behaviour (functionality) and data together.

There are inherent problems using class diagrams to model data. Very oftern when you're finished you have to perform 'object to database mappings ' to have something of value.

One example is that class diagraming allows what is termed many to many associations between classes, whereas in logical data modeling this is considered bad practice.

The advantage to class diagrams is that you discover the functionality or behavior of classes. There are ways to do this with logical models, but they're not inherent to logical data modeling.

When or Why to use What - If you're development team is HONESTLY REALLY TRUTHFULLY using object oriented development. (Most places don't really do this) - UML and Class Diagrams work well with this

If you're using other methods of development (coding) or not true OO.... then you won't gain any advantage in UML.

Being a data modeler by nature..... I favor logical and physical data models.

Vmuisc
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Old 01-08-05, 13:55
r937 r937 is offline
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i think the title begs the question

" ... in the field of DBS" use data models
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Last edited by r937; 01-08-05 at 13:59.
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