The Data warehouse used some tools. What are the functions?

Data warehouse systems use back-end tools and utilities to populate and refresh their data. These tools and facilities include the following functions—

1 Data Extraction —

it typically gathers data from multiple, heterogeneous, and external sources.

2 Data Cleaning —

This detects errors in the data and rectifies them when possible.

3 Data Transformation —

It converts data from legacy or host format to warehouse format.

4 Load —

It sorts, stmunariz.es, consolidates, computes views, checks integrity. and builds indices and partitions.

5 Refresh —

It propagates the updates from the data sources to the warehouse.

Besides cleaning, loading, refreshing, and metadata definition tools, data warehouse systems usually provide a good set of data warehouse management tools. Data cleansing and data transformation are important steps in improving the quality of the data and, subsequently, of the data mining results.