this paper, some interesting issues related to vertical partitioning in object oriented database systems are presented. A review of existing research is given with an identification of some open problems. A taxonomy of various possible partitioning schemes and a unified view of the vertical partitioning problem are also presented. Existing vertical partitioning algorithms have been studied for their use in both parallel and distributed object-oriented databases

The objective of object oriented databases is to respond to the needs of new applications as engineering and multimedia which manipulate complex data. Furthermore, most of these applications need to execute in a distributed environment, making necessary the distribution of data on different sites. This must garantee a minimum cost of inter-site communication and minimum access to irrelevant data. Data distribution has largely been studied in the relational model, but the complex structure of objects and their relationships make it difficult for object oriented databases. In this paper, both fragmentation and allocation problems are tackeled. Hybrid fragments are defined by applying horizontal fragmentation followed by vertical fragmentation to each database class. Resulting fragments are disjoint regarding to data but overlapping regarding to methods. An optimisation model for a nonreplicated data allocation in the form of a non linear integer zero-one programming problem is also develo...