A sample text widget

Etiam pulvinar consectetur dolor sed malesuada. Ut convallis euismod dolor nec pretium. Nunc ut tristique massa.

Nam sodales mi vitae dolor ullamcorper et vulputate enim accumsan. Morbi orci magna, tincidunt vitae molestie nec, molestie at mi. Nulla nulla lorem, suscipit in posuere in, interdum non magna.

Functionality of Data Warehouses and Building a Data Warehouse

Data warehouses exist to facilitate complex, data-intensive, and frequent adhoc queries. The data warehouse access component supports enhanced spreadsheet functionality, efficient query processing, structured and adhoc queries, data mining, and materialized views. These offer pre-programmed functionalities such as :
– Roll-up : Data is summarized with increasing generalization.
– Drill-down : Increasing levels of details are revealed.
– Pivot : Cross tabulation is performed.
– Slice and dice : Performing projection operations on the dimensions.
– Sorting : Data is sorted by ordinal value.
– Selection : Data is available by value or range.
– Derived attributes : Attributes are computed by operations on stored and derived values.

In constructing a data warehouse, builders should take a broad view of the anticipated use of the data warehouse. Acquisition of data for the warehouse involves the following steps :
– The data must be extracted from different sources.
– Data must be formatted for consistency within the data warehouse. Names, meanings, and domains of data from unrelated sources must be reconciled.
– Data must be cleaned to ensure validity.
– The data must be fitted into the data model of the data warehouse.
– The data must be loaded into the warehouse.
– How up-to-date must be data be ?
* Can the warehouse go off-line, and for how long.
* What are the data interdependencies ?
* What is the storage availability ?
* What are the distribution requirements ?
* What is the loading time ?
Data warehouses must also be designed with full consideration of the environment in which they will reside. Important design considerations include the following :
– Usage projections.
– The fit of the data model.
– Characteristics of available sources.
– Design of the metadata component.
– Modular component design.
– Design for manageability and change.
– Consideration of distributed and parallel architecture.

Leave a Reply

You can use these HTML tags

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>