Distributed applications are broadly used due the existence of mobile devices as are mobile phones, tablets and chrome books. They are often based on an architecture client-server. A server part contains a central storage where all application data are stored. A specific user accesses data using a client part of an application. The client part of the application can store data in its local storage to enable an offline mode. In the past, we were developing such a client-server software system and we realized that it doesn't exists a general way how to define, search and provide into a client part only those data that are important or relevant to a particular user. The aim of this article is a definition of the problem and a creation of its general solution, not how to achieve the most effective and complete data synchronization. Complete synchronization of data that has been already theoretically and practically solved on a general level and it is impractical for our case