1. A knowledge base system of a computer system that executes a knowledge base, comprising: a recording medium, readable by a computer, that stores a knowledge base file, said knowledge base file comprising: an output knowledge variable; knowledge variables that operate said output knowledge variable; and a computing equation of declarative representation that utilizes said knowledge variables using operands as other knowledge variables, and means for executing said knowledge base in the computers comprising: means for translating said computing equation of declarative representation into a computer program; means for retrieving dependence of said output knowledge variable on other knowledge variables; means for setting an execution sequence of said computer program with reference to said dependence; and means for making one of an input request to a user and for executing said computer program with reference to said set execution sequence, wherein said means for setting an execution sequence comprises: means for controlling one of operated and non-operated attributes for respective knowledge variables; and means for carrying up said execution sequence of said computer program concerning a non-operated knowledge variable referred by said executing means executing another program having an operand of said non-operated knowledge variable.