Data warehouse toolkit notes
Operational systems turn the wheels of the organisation.
Operational systems perform the same tasks repeatedly, often only updating a single record at a time.
Operational systems will most often reflect the most current state. They typically do not maintain history.
DW/BI - Data Warehouse / Business Intelligence
DW/BI users watch the wheels of the organisation turn to evaluate performance.
DW/BI users evaluate if processes are working correctly and efficiently.
DW/BI systems often need to search across thousands of transactions, that are summarised in an answer set.
DW/BI systems typically demand that historical context be preserved.
Typical DW/BI system requirements include:
The DW/BI system must make information easily accessible
- contents of DW/BI system must be understandable
- the data must be intuitive
- data structures should mimic business users thought processes
- the BI tools to access data should be simple and easy to use
The DW/BI system must present information consistently
- data in DW/BI system must be credible
- data should be cleaned, quality assured
- data should only be released when fit for user consumption
- consitent naming and labeling across data sources.
The DW/BI system must adapt to change
- the DW/BI system must be designed to handle change gracefully.
- existing data should not be changed or disrupted when the business community asks new questions.
- If data in DW/BI system does change these changes should be made transparent to users.
The DW/BI system must present information in a timely way
- Raw data may need to be converted within minutes.
The DW/BI system must be secure
- Often critical information (eg costs) are in the data warehouse
- The DW/BI system must effectively control access to this confidential information
The DW/BI system must serve as the authoritative foundation for improved decision making
- decisions are the most important output form a DW/BI system
- these decisions are based on analytic evidence
- you are designing a DECISION SUPPORT SYSTEM
The business community must accept the DW/BI system to deem in successful
- If the business community does not embrace the DW/BI environment and use it you have failed the acceptance test.
- DW/BI usage is often optional
- Business users will adopt DW/BI systems if it is a simple and fast source of information
A DW/BI manager responsibilities
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Dimensional Modeling Introduction
Dimensional modeling is widely accepted as it addresses two main requirements
- Deliver dat that's understandable to business users
- Deliver fast query performance