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GeekInterview.com > Interview Questions > Management > Business Analyst
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Question: What is the difference between data model and an entity relationship diagram?
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| February 02, 2007 02:10:02 |
#1 |
| Shridatt Kelkar |
Member Since: Visitor Total Comments: N/A |
RE: What is the difference between data model and an e...
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| A data model is a model which shows how data is stored and used for eg a normal databaseIt has 3 main parts1)Structural part:- how data is structured2)Intergrity part:- Rules governing structure3)Manipulation part:- operators used to select,update,querry that data,eg select,update,delete commands in sqlTo furhter add Data Modelling is when we add this theory to Live instance.ENTERPRISE DATA MODEL(ENTERPRISE RELATIONSHIP MODELING) :- This can be called as an conceptual model or semantic modelThe sub parts of an ERM are1)Entity:- It is an object,eg employees,computer2) Relationship:- It captures how two or more entities are related to each other3)Attributes:- Every entity has its own sets of atributes (eg PAN no in India for each employee or SSN in US)To clarify the point look at egA employye is an entity belonging to entity sets(All employees) which has a relationship with department,and attributes is emp code |
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