Shared database is the preferred way of doing cross-system interoperability. The database handles a range of data types, the network communication issues, and transactions and serialization. Database replication is often a requirement. With homogeneous data- bases, this is commonly provided; MySQL and PostgreSQL both support replication as a database feature. We can also manage replication with scripting. For complex replication needs involving several heterogeneous databases, it is worth considering products such as Golden Gate.