No, that's not correct.  Deductive reasoning is the kind of logic most often used by judges when deciding a case.  Principles and rules of law are used as the major premises with which the reasoning begins, followed by statements of fact, leading to a conclusion.

However,  inductive reasoning is sometimes used, particularly when there does not appear to be a pre-existing rule of law that properly applies to the case that has arisen.  In such circumstances, conclusions are drawn from particular facts, from which decision legal rules can be inferred for future cases.