The author conceived this work as a scientific work intended for educational and study use for all those who approach the study of databases and which can also be used for business purposes. The author is convinced that everyone should know the Databases that could solve various problems. In this globalized and complex world where information is multiple and widespread, the needs are many and require people who know composite models of data analysis. Today the Databases are used in all applications available to the public. Computer applications that are downloaded to mobile devices also contain databases for storing and extracting data. The simple username and password that we enter to access our online profile is nothing more than a database containing all the data entered by the user upon registration. In this work the author will accompany you on a complete path from the identification of the problem to be solved, to the preparation of the conceptual model, to the construction of the physical database with the creation of the application that will lead to the required solution. The author has prepared some examples in Access, Visual Basic, Pascal as well as an example of Database application in Html and Php just to highlight the multiplicity of possible uses of the Databases.