Three-Layers Model Designing in the Logical Level Data Warehouse

The operational databases and online transaction processing systems are appropriate structures for maintenance and collection of data, but the challenge of structures is how to use and interpret this data. A data warehouse is a data source which collects data from other systems and data sources such as operational data bases, users systems, and etc; and stores and categorizes data in the form of multidimensional after homogenization and integration. This data source for reporting operation, analysis, to help make decisions and business intelligence. The process of developing a data warehouse is done through operational data base analyzing, analytical requirement identification and finally designing in conceptual, logical and physical levels. In this paper, the designing models at logical level of data warehouses are researched. Then an improved model is presented in this level that combines of three models (snow flake, star cluster and star) in the form of a three - layers. Queries response time measure is used to compare the proposed model with existing models. Experiments show that the proposed model improves the response time of queries.