Ralph Kimball vs. Bill Inmon

I came Across this wonderful comparison between Ralph Kimball and Bill Inmon in the way data marts Should be built I decided to share it on my blog for your reference

Areas of agreement

• Consensus on need for solid business requirements and end-user validation
• Agreement that it is rarely feasible to build an entire warehouse at once - incremental development with a focus on high-priority elements
• Conformed dimensions are desirable
• Warehouse data needs to be tracked as atomically as possible
• Star schema is most desirable format for data marts

Areas of differences

• Bill Inmon
  • Approach is known as Top-Down, or Corporate Information Factory
  • Warehouse data should be stored in a centralized relational structure
  • Dependent data marts should be created from central warehouse
    • These data marts will employ star schemas
    • Additional transformations may be employed between the warehouse and the data marts
  • ODS is used for transaction level detail with little to no history

Inmon Kimball

• Ralph Kimball
  • Approach is known as Bottom-Up, or Kimball Bus Architecture
  • “… The data warehouse is nothing more than the union of all the data marts …”
  • Conformed dimensions are the glue which unite disparate data marts, while Inmon maintains conformed dimensions within centralized relational structure
  • ODS may be integrated directly into warehouse