Data Warehousing

Data Warehousing

1. A physical repository where relational data are specially organized to provide enterprise-wide, cleansed data in a standardized format

2. Characteristic

   • Time-Variant
   • Non Volatile
   • Meta-Data
   • Integrated
   • Subject Orientated
   • Summarized
   • Web-Based
   • Relational/ Multidimensional
   • Client/Server
   • Real-Time

3. Types

   • Enterprise Data Warehouse
   • Operational Data Stores
   • Data Marts

4. ETL Process

   • Extract
     • Transform
       • Load

5. Representation of Data in DW

   • Multi-dimensional Presentation
     • Dimension
     • Measures
     • Time
   • Schemas
     • Star
     • Snowflake
     • Constellation

6. OLAP

   • Operations
     • Slice
     • Dice
     • Drill Down/UP
     • Rollup
     • Pivot
     • Drill Through
   • Variations
     • ROLAP
     • MOLAP
     • HOLAP