Data Warehouse concepts

Defining Data Warehouse Concepts and Terminology

Definition of a Data Warehouse: “An enterprise structured repository of subject-oriented, time-variant, historical data used for information retrieval and decision support. The data warehouse stores atomic and summary data.”

Data Warehouse Properties

1. Subject-Oriented:

Data is categorized and stored by business subject rather than by application.

2. Integrated:

Data on a given subject is defined and stored once.

3. Time variant:

Data is stored as a series of snapshots, each representing a period of time

4. Non-volatile:

Typically data in the data warehouse is not updated or deleted.

Difference between Data warehouse and Data Mart

Methodology

1. Ensures a successful data warehouse
2. Encourages incremental development
3. Provides a staged approach to an enterprise wide warehouse   

     - Safe

     -  Manageable

     - Proven

     - Recommended

Modeling:

 1. Warehouses differ from operational structures:

      - Analytical requirements

      - Subject orientation

2. Data must map to subject oriented information:

      - Identify business subjects

      - Define relationships between subjects

      - Name the attributes of each subject

3. Modeling is iterative

 4. Modeling tools are available

Data Management:

1.Efficient  database server and management  tools for all aspects of data  management

2.Imperatives

     - Productive

     - Flexible

     - Robust

     - Efficient

3.Hardware, operating system and network management