In a world today because of wide range of Internet access and digital transformation, development or usage of web application, be it for private or business purposes is inevitable. Not taking into account the specific purpose of web application it is a given that data, generated from users or application developers, needs to be stored somewhere. For that reason databases are one of the integral parts in web application development process. Despite emergence of new technologies and new types of databases, relational databases are still very current and widely used. This thesis describes the theoretical foundations of the relational databases, while in the practical part all the steps in the process of creating a relational database for specific web application are presented systematically. The analysis of functional specification shows the conceptual model of the database and the ER model, while the logical model shows the relational model, later implemented in Microsoft SQL Server. Web application logic is implemented via SQL written procedures and triggers.