This paper reports the result of testing the author's proof techniques on the class of constraint satisfaction problems (CSP). This experiment has been successful in the sense that a completely general proof technique turns out to behave well also for this special class of problems which itself has received considerable attention in the community. So at the same time the paper happens to present a new (deductive) mechanism for solving constraint satisfaction problems that is of interest in its own right. This mechanism may be characterized as a bottom-up, lazy-evaluation technique which reduces any such problem to the problem of evaluating a database expression typically involving a number of joins. A way of computing such an expression is proposed.