A data model in software engineering is an abstract model that describes how data is represented and accessed. Data models formally define data elements and relationships among data elements for a domain of interest. Data model explicitly determines the meaning of data, which in this case is known as structured data (as opposed to unstructured data, for example an image, a binary file or a natural language text, where the meaning has to be elaborated). Typical applications of data models include database models, design of information systems, and enabling exchange of data. Usually data models are specified in a data modeling language. A data model can be sometimes referred to as a data structure, especially in the context of programming languages. Data models are often complemented by function models, especially in the context of enterprise models.