This paper presents an investigation into approaches and techniques used for database conversion. Constructing object views on top of a Relational DataBase (RDB), simple database integration and database migration are among these approaches. We present a categorisation of selected works proposed in the literature and translation techniques used for the problem of database conversion, concentrating on migrating an RDB as source into object-based and XML databases as targets. Database migration from the source into each of the targets is discussed in detail including semantic enrichment, schema translation and data conversion. Based on a detailed analysis of the existing literature, we conclude that an existing RDB can be migrated into object-based/XML databases according to available database standards. We propose an integrated method for migrating an RDB into object-based/XML databases using an intermediate Canonical Data Model (CDM), which enriches the source database's semantics and captures characteristics of the target databases. A prototype has been implemented which successfully translates CDM into object-oriented (ODMG 3.0 ODL), object-relational (Oracle 10g) and XML schemas.