Efficient decomposing of databases is a problem. Sometimes, a database is designed in such a way that it is hard to decompose it or it requires a major design change in DB tables. Is the organization ready to take that hit? Is it feasible to break down one big DB into much smaller databases that are logically and physically different from each other? As data is in the decentralized form and resides in different databases, it means there will be no physical connection at tables. It leads to major changes in code bases.