Semantic Technologies Applying to Data Warehouses Federation

Business intelligence is based on the existence of main components including : data warehouses .The data warehouse is a specialized database which main task is to provide quick access to data in analysis objective. But in some cases it is necessary to use a set of data warehouses to provide a complete information . This structure is what we  call federation, and even if the components are physically separated, they are logically seen as a single component. Generally, these items are heterogeneous which make it difficult to create the logical federation schema ,and the execution of user queries a complicated mission. In this paper,  we will fill this gap by proposing a model for logical federation schema creation based on ontology, in order to treat different schema types (star , snow flack) including the treatment of hierarchies dimension too.