This paper aims to study the Conceptual Tools used in Conceptual Modeling of Database, so that Benefit of Extending these Tool used in Effective Relational Database Design could be found out. In this study, we investigated two application examples, through which two Conceptual diagrams were used to build Relational Database. The main result of this study was, the benefit from the extending the Conceptual Tools for designing a Relational Database could be achieved when this extension to Tools used in building is applicable to the Database. Since the Conceptual Modeling stage of the Database, has to be simple and clear, the extension is not recommended for modeling Conceptual diagrams of large systems, which has time limits.