Monday, July 17, 2017

Data Modelling

ER Diagram is the first step to build datawarehouse model

Entity Relation model

Data Modelling: An archirects job. 


Tables that makeup the warehouse are mentioned, the relationship between the tables is mentioned. the primary and foriegn keys are also mentioned.

3 Types of data models:


1. Conceptual Data model: 

First step, High level overview of datawarehouse.
Primarly for business consumers, very less technical details and not useful for developers.
Just gives information about the related tables. No primary and foriegn key specification.
2. Logical Data model; an extension to conception data model.
Specifies the keys/attributes in the tables relation. 
primary and foriegn keys are specified.
columns involved in each table.

3. Physical data model: Datatypes for each column, Not NULLS
Views procedures and Indexes will also be specified.



Types of datawarehouse designs:

Agile Datawarehouse design

Dimentional modelling

1 comment:

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