The structure consists of the following:
Physical Data Warehouse: Physical database in which all the data for the Warehouse are stored, along with metadata and processing logic for scrubbing, organizing, packaging and processing the detail data.
logical data Warehouse: Also contains metadata, including enterprise rules processing logic for scrubbing, organizing, packaging and processing data, but does not contain actual data. Instead, it contains the information necessary to access the data whenever they reside. This structure is effective only when there is a/.single source for the data and when the data in the source is accurate and'timely.
Data mart is a subset of an enterprise - wide pata Warehouse,which typically supports and enterprise element (department, region, function, etc.). As part of an iterative Data Warehouse development process, an enterprise build a series of physical (or logical) data marts over time and links them via an enterprise - wide logical Data Warehouse or feeds them from a single physical warehouse.
Ten mistakes to be avoided In a Data Warehousing Project
1. Starting the data warehousing project without the right sponsorship and top management support.
2. Setting expectations that you cannot meet and frustrating executives at the moment of truth.
3. Promising the value of the data warehouse with arguments to the effect of, This will help managers make better decisions' which can backfire.
4. Loading the warehousa with information 'just because it was available.
5. Believing that Data Warehousing database design is the same as transactional database design.
6. Choosing a Data Warehousing manager who is technology oriented rather than user oriented.
7. Focusing on traditional internal record oriented data and ignoring the potential value of external data and of text, images, and - potentially - sound and video.
8. Delivering data with overlapping and confusing definitions.
9. Believing the performance, capacity and scalability promises.
10. Believing that once the data warehouse is up and running, your problems are finished.
Source: the Data Warehousing Institute (TDWI), |
