Data location
Warehousing vs. Virtual (on-line) sources
- Warehousing avoids the problems of the net
- Data may get stale.
- There may be too much data.
- You may not be allowed to shift the data over
- Virtual Source method accesses the sources on demand
- Has to handle internet problems such as
- bursty traffic, setup delays etc.
- Hybrid
- Selective materialization; Caching etc...