This paper introduces a probabilistic relational database model, called PRDB, for representing and querying uncertain information of objects in practice. To develop the PRDB model, first, we represent the relational attribute value as a pair of probabilistic distributions on a set for modeling the possibility that the attribute can take one of the values of the set with a probability belonging to the interval which is inferred from the pair of probabilistic distributions | Journal of Computer Science and Cybernetics, , (2015), 305–321 DOI: A PROBABILISTIC RELATIONAL DATABASE MODEL AND ALGEBRA NGUYEN HOA Department of Information Technology, Saigon University; nguyenhoa@ Abstract. This paper introduces a probabilistic relational database model, called PRDB, for representing and querying uncertain information of objects in practice. To develop the PRDB model, first, we represent the relational attribute value as a pair of probabilistic distributions on a set for modeling the possibility that the attribute can take one of the values of the set with a probability belonging to the interval which is inferred from the pair of probabilistic distributions. Next, on the basis representing such attribute values, we formally define the notions as the schema, relation, probabilistic functional dependency and probabilistic relational algebraic operations for PRDB. In addition, a set of the properties of the probabilistic relational algebraic operations in PRDB also are formulated and proven. Keywords. Probability distribution, probabilistic triple, probabilistic relation, probabilistic functional dependency, probabilistic relational algebraic operation 1. INTRODUCTION As we all know, the classical relational database model is very useful for modeling, designing and implementing large-scale systems. However, this model is restricted for representing and handling uncertain and imperfect information of objects in the real world [1, 2]. For example, applications of the classical relational database model cannot deal with queries as find all players that are 80-90% likely to be the top scorers of English Premier League, in year 2015; nor find all patients who are at least 70% likely to catch a cirrhosis or hepatitis, etc. So far, there have been many relational database models studied, developed and built based on the probability theory for modeling objects about which information may be uncertain and .
