Hierarchy Classification for Data Warehouse: A Survey

In data warehouse systems, the hierarchies play a key role in processing and monitoring information. These hierarchies dynamically analyze huge volumes of historical data in data warehouses at various granularity levels using OLAP operations like roll-up and drill-down. Through these operations we can get summarized as well as detailed data which aids in analysis as well as decision making process. Several authors have defined hierarchies deriving from real-world applications in order to represent broad range of business scenarios. But there is a need to properly categorize dimension hierarchies so as to adequately model them during evolution. In this paper we have provided a comprehensive comparison of different categories of hierarchies proposed by various researchers based on certain parameters.