1. A computer-based method implemented in a query optimizer to incorporate partial information about multivariate distributions in a constrained optimization form, said method comprising: modeling one or more multivariate distributions based on available statistical information in a probability space; modeling one or more multivariate distributions for which no statistical information is available via a constrained optimization approach and entropy maximization over said probability space, and said query optimizer using all available statistical information and both of said modeled distributions during cardinality estimation.