Abstract
Heterogeneous databases are now facing an emerging challenge of moving towards big data. These databases are adhoc polyglot systems, complex, and NoSQL tools which are semantically annotated. Integration of these heterogeneous databases are becoming very challenging because big data analytics is integrating human and machines contexts. In this paper, an attempt is made to study heterogeneous databases and their interoperability issues and integration issues, and their impact on analysis of data. The data science has grown exponentially and a new paradigm has emerged which is of integration of heterogeneous data to big data. Information, knowledge and decision making become easier but the size of databases has grown and it became big data.