Survey on the management of uncertain data

The importance of the data uncertainty was studied deeply with the rapid development in data gathering and processing in various fields, inclusive of economy, military, logistic, finance and telecommunication, etc. Uncertain data has many different styles, such as relational data, semistructured data, streaming data, and moving objects. According to scenarios and data characteristics, tens of data models have been developed, stemming from the core possible world model that contains a huge number of the possible world instances with the sum of probabilities equal to 1. However, the number of the possible world instances is far greater than the volume of the uncertain database, making it infeasible to combine medial results generated from all of possible world instances for the final query results. Thus, some heuristic techniques, such as ordering, pruning, must be used to reduce the computation cost for the high efficiency. This paper introduces the concepts, characteristics and challenges in uncertain data management, proposes the advance of the research on uncertain data management, including data model, preprocessing, integrating, storage, indexing, and query processing.