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Subject: search.filters.subject.Object-oriented databases

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    An object-oriented database methodology for application development with extended relational or object-oriented DBMS : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Computer Science at Massey University
    (Massey University, 1992) Liew, Benny
    Recently development methodologies have been proposed which describe themselves as "Object Oriented". While all of them offer approaches to extended data and behavioural modelling, none of them seem fully adequate to address the total concept of object-oriented development. They often do not provide constructs which lead to the use of databases, nor do they always recognise the shift from sequential to prototyping style which is inherent in much object-oriented technology. The objective of this thesis is to lay a framework for an object-oriented methodology suitable for OODBMS. Details of conventional methods for developing database applications, and of the recent OO methods, have been examined and compared in order to propose a coherent set of tasks and deliverables. Account has also been taken of designing for re-use, which has been one of the main selling points of the OO approach. The proposed methodology attempts to address related side issues, with particular focus on object concurrency, which seems particularly thinly covered in many of the current proposals. Many other side issues are also mentioned, but due to time constraints, they are not given any further discussion. The topic is an extremely multidisciplinary one, and a very wide range of expertise would be necessary to do justice to all these aspects. Mapping of the new methodology has been tried on two case study examples using Postgres and Ontos. Postgres is an extended relational DBMS developed as a research prototype at University of California, Berkeley. Ontos is the commercial object-oriented DBMS marketed by Ontos Incorporated, Burlington, Massachusetts. Some details of these implementation examples are included.
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    Associative access in persistent object stores : a thesis presented in partial fulfilment of the requirements for the degree of Master of Information Sciences in Information Systems at Massey University
    (Massey University, 2004) Nusdin, Weena
    The overall aim of the thesis is to study associative access in a Persistent Object Store (POS) providing necessary object storage and retrieval capabilities to an Object Oriented Database System (OODBS) (Delis, Kanitkar & Kollios, 1998 cited in Kirchberg & Tretiakov, 2002). Associative access in an OODBS often includes navigational access to referenced or referencing objects of the object being accessed (Kim. Kim. & Dale. 1989). The thesis reviews several existing approaches proposed to support associative and navigational access in an OODBS. It was found that the existing approaches proposed for associative access could not perform well when queries involve multiple paths or inheritance hierarchies. The thesis studies how associative access can be supported in a POS regardless of paths or inheritance hierarchies involved with a query. The thesis proposes extensions to a model of a POS such that approaches that are proposed for navigational access can be used to support associative access in the extended POS. The extensions include (1) approaches to cluster storage objects in a POS on their storage classes or values of attributes, and (2) approaches to distinguish references between storage objects in a POS based on criteria such as reference types - inheritance and association, storage classes of referenced storage objects or referencing storage objects, and reference names. The thesis implements Matrix-Index Coding (MIC) approach with the extended POS by several coding techniques. The implementation demonstrates that (1) a model of a POS extended by proposed extensions is capable of supporting associative access in an OODBS and (2) the MIC implemented with the extended POS can support a query that requires associative access in an OODBS and involves multiple paths or inheritance hierarchies. The implementation also provides proof of the concepts suggested by Kirchberg & Tretiakov (2002) that (1) the MIC can be made independent from a coding technique, and (2) data compression techniques should be considered as appropriate alternatives to implement the MIC because they could reduce the storage size required.
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    Distribution design in object oriented databases : a thesis presented in partial fulfilment of the requirements for the degree of Master of Information Science in Information Systems
    (Massey University, 2003) Ma, Hui
    The advanced development of object oriented database systems has attracted much research. However, very few of them contribute to the distribution design of object oriented databases. The main tasks of distribution design are fragmenting the database schema and allocating the fragments to different sites of a network. The aim of fragmentation and allocation is to improve the performance and increase the availability of a database system. Even though much research has been done on distributed databases, the research almost always refers to the relational data model (RDM). Very few efforts provide distribution design techniques for distributed object oriented databases. The aim of this work is to generalise distribution design techniques from relational databases for object oriented databases. First, the characteristics of distributed databases in general and the techniques used for fragmentation and allocation for the RDM are reviewed. Then, fragmentation operations for a rather generic object oriented data model (OODM) are developed. As with the RDM, these operations include horizontal and vertical fragmentation. A third operation named splitting is also introduced for OODM. Finally, normal predicates are introduced for OODM. A heuristic procedure for horizontal fragmenting of OODBs is also presented. The adaption of horizontal fragmentation techniques for relational databases to object oriented databases is the main result of this work.