The Role of Metadata for Effective Data Warehouse

Metadata efficient method for managing data warehouse (dw). it is also an effective tool in reducing the time or speed to answer queries. in addition, it achieved capabilities of the integration and standardization, thus lead to faster, clear and accurate decision-making in the right time. this paper provides the definition of metadata concept, and using metadata in data cleaning; which it identify the sources, types of fields, and choose the appropriate algorithm. in addition, useful in decision support system (dss); which it improve efficiency of analysis and reduces response time of query.