Data-Warehouse Designing

1. Conceptual Data Model - Design Step 1

This is First step for DWH Designing.

Conceptual Data Model is the first step in Data Warehouse design. In conceptual data model, very high level relationships between dimension and fact table is depicted. Conceptual data model not necessarily includes keys, attributes of tables. Conceptual data model gives a very high level idea of proposed Data Warehouse design including possible fact and dimension table. Conceptual data model is the stepping stone to design logical data model of Data Warehouse.

Characteristics of Data Warehouse Conceptual Data Model

It shows only high level relationship between tables.

It does not show primary key or column names

It is the stepping stone of Logical Data Model

2. Logical Data Model - Design Step -2

This is Second step for Designing

Good Logical data model in data warehouse implementation is very important. Logical data model has to be detailed (though some might not agree) as it represents the entire business in one shot and shows relationship between business entities. Logical Model should have following things to make it detailed and self explanatory.

All entities to be included in data warehouse

All possible attributes of each entity

Primary keys of each entity ( Natural Keys as well as Surrogate Keys )

Relationships between each every entity

Characteristics of Data Warehouse Logical Data Model

It has all the entities which will be used in data warehouse

It shows all possible attributes of all entities

It depicts the relationships between all entities

3. Physical Data Model - Design Step -3

This is third step for Designing for DWH Design

Physical Data Model is the actual model which will be created in the database to store the data. It is the most detailed data model in Data Warehouse data modeling. It includes

Tables names

All column names of the table along with data type and size

Primary keys, Foreign Keys of a table , Constraints

Physical Data Model can be converted to actual SQL DDL statement by using different tools. ERWIN is the famous tool to do this.

Comments

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