In a business process, the information that flows between the activities can be introduced by those users who interact with the process. This introduced information could be incorrect due to a lack of knowledge or a mistake. For this reason and to make the business process execution consistent, we propose a Decision Support System (DSS) to inform the user about the possible and correct values that the input data can take. The DSS takes into account the business process model and the policy of the company. The policy concerning the input data and dataflow that the company manages can be represented by constraints (called Business Data Constraints (BDCs)). In order to ascertain all the possible values of the input data that permit the execution of the process following the defined goals, the DSS analyzes the business process model and the BDC, using the constraint programming paradigm.