what is data modelling? what are types of modelling?In
which suituation will use each one?
Answer / mike
Data modelling: It is the process of designing a a datamart
or dataware house. there are three phases in data modeling
1)conceptual designing:In this phase the database
architects and the managers will understand the client
requirements. After understanding the requirements they
will identify the attributes and entities(colomns and
tables)
2)Logical designing:In this phase the dimension tables and
the fact tables are identified and also the relation ship
between the fact and dimension tables will gets identified.
Now the schema looks like either a star or snowflake
schema. To perform logical designing we use data modelling
tools like ER STUDIO or ERWIN.
3)Physical designing: Once the logical designing is
approved by the client it will be converted in to physical
existance in the database.
Hope this helps
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