Object-relational Database Systems Research Articles

Towards the Maturity of Object-Relational Database Technology: Promises and Reality

Object-relational technology provides a significant increase in scalability and flexibility over the traditional relational databases. The additional object-relational features are particularly satisfying for advanced database applications that relational database systems have experienced difficulties. The key factor to the success of object-relational database systems is their performance. This paper aims to review the promises of Object-Relational database systems, examine the reality, and how their promises may be fulfilled through unification with the relational technology. To investigate the performance implications of using object-relational relative to relational technology, the query-oriented BUCKY benchmark has been previously applied to an early object-relational database system, i.e., Illustra 97. This paper presents the results obtained from implementing and running the BUCKY benchmark on Oracle 10g. The results acquired from the work described in this paper are compared with the results obtained in BUCKY benchmark. This study throws light on the functionality of object-relational databases, where object-relational technology has made improvements but some limitations are identified as well. In general, the performance of relational supersedes that of object-relational database system.

Reason based Access Control for Privacy Protection in Object Relational Database Systems

Reason based Access Control for Privacy Protection in Object Relational Database Systems

Scientific formats for object-relational database systems

Commercial database management systems (DBMSs) have historically seen very limited use within the scientific computing community. One reason for this absence is that previous database systems lacked support for the extensible data structures and performance features required within a high-performance computing context. However, database vendors have recently enhanced the functionality of their systems by adding object extensions to the relational engine. In principle, these extensions allow for the representation of a rich collection of scientific datatypes and common statistical operations. Utilizing these new extensions, this paper presents a study of the suitability of incorporating two popular scientific formats, NetCDF and HDF, into an object-relational system. To assess the performance of the database approach, a series of solution variables from a regional weather forecast model are used to build representative small, medium and large databases. Common statistical operations and array element queries are then performed using the object-relational database, and the execution timings are compared against native NetCDF and HDF operations.

Stonebraker receives IEEE John von Neumann Medal

In December 2004, Michael Stonebraker was selected to receive the 2005 IEEE John von Neumann Medal for his "contributions to the design, implementation, and commercialization of relational and object-relational database systems." Mike is the first person from the database field selected to receive this award. He joins an illustrious group of former recipients, including Barbara Liskov (2004), Alfred Aho (2003), Ole-Johan Dahl and Kristen Nygaard (2002), Butler Lampson (2001), John Hennessy and David Patterson (2000), Douglas Engelbart (1999), Ivan Sutherland (1998), Maurice Wilkes (1997), Carver Mead (1996), Donald Knuth (1995), John Cocke (1994), Fred Brooks (1993), and Gordon Bell (1992).

Using UML class diagrams for a comparative analysis of relational, object-oriented, and object-relational database mappings

This paper illustrates the manner in which UML can be used to study mappings to different types of database systems. After introducing UML through a comparison to the EER model, UML diagrams are used to teach different approaches for mapping conceptual designs to the relational model. As we cover object-oriented and object-relational database systems, different features of UML are used over the same enterprise example to help students understand mapping alternatives for each model. Students are required to compare and contrast the mappings in each model as part of the learning process. For object-oriented and object-relational database systems, we address mappings to the ODMG and SQL99 standards in addition to specific commercial implementations.

Object-relational database systems — the road ahead

Object-relational database systems — the road ahead

Advanced database concepts for undergraduates

This paper describes the development of a second database course for undergraduates, preparing students for the advanced database concepts they will experience in industry. Assuming an introductory course on relational database systems as a prerequisite, the topics addressed in the course include object-oriented data modeling, object-oriented database systems, object-relational database systems, Web access to databases, and professionalism and ethics. We present our experience with teaching the course, elaborating on the topics and assignments. We also present feedback from students and industry partners as well as our own assessment of future course refinements.

Querying XML documents

Web based environments will typically need to maintain many documents (e.g. simulation model information and data results from multiple sites). Ideally, this information would be held in a widely utilized and highly viewable format. The eXtensible Markup Language (XML) is a new standard that meets this criteria for World Wide Web based applications. It is sophisticated enough so that complex real world structures and relationships may be captured. Large collections of XML documents can be stored for efficient retrieval using database management systems (DBMSs). Current database management is represented by the object oriented (OO) and object-relational (OR) database systems. Each type has their own query languages, Object Query Language (OQL, v.2) and Structured Query Language (SQL), respectively. These database query languages provide a high-level way to ask for information from a database. The article looks at storing and retrieving XML documents. It surveys work being done on query languages and tools for XML. It then discusses a simple graphical XML query tool for front end use in the Java Simulation (JSIM) Web based simulation environment.

Cost estimation of user-defined methods in object-relational database systems

In this paper we present a novel technique for cost estimation of user-defined methods in advanced database systems. This technique is based on multi-dimensional histograms. We explain how the system collects statistics on the method that a database user defines and adds to the system. From these statistics a multi-dimensional histogram is built. Afterwards, this histrogram can be used for estimating the cost of the target method whenever this method is referenced in a query. This cost estimation is needed by the optimizer of the database system since this cost estimation needs to know the cost of a method in order to place it at its optimal position in the Query Execution Plan (QEP). We explain here how our technique works and we provide an example to better verify its functionality.

Database patchwork on the Internet

Naturally, data processing requires three kinds of resources: the data itself, the functionality (i.e. database operations) and the machines on which to run the operations. Because of the Internet we believe that in the long run there will be alternative providers for all of these three resources for any given application. Data providers will bring more and more data and more and more different kinds of data to the net. Likewise, function providers will develop new methods to process and work with the data; e.g., function providers might develop new algorithms to compress data or to produce thumbnails out of large images and try to sell these on the Internet. It is also conceivable, that some people allow other people to use spare cycles of their idle machines in the Internet (as in the Condor system of the University of Wisconsin) or that some companies ( cycle providers ) even specialize on selling computing time to businesses that occasionally need to carry out very complex operations for which regular hardware is not sufficient. At the University of Passau, we are currently developing a distributed database system to be used in the Internet. The goal is to ultimately have a system which is able to run on any machine, manage any kind of data, import any kind of data from other systems and import any kind of database operations. The system is entirely written in Java. One of the most important features of the system is that it is capable of dynamically loading (external) query operators, written in Java and supplied by any function provider, and executing these query operators in concert with pre-defined and other external operators in order to evaluate a query. Compared to object-relational database systems, which allow to integrate external data and functionality by the means of extensions (datablades, extenders or cartridges) or heterogeneous database systems such as Garlic [MS97] or Tsimmis [GMPQ + 97], our approach makes it possible to place external query operators anywhere in a query evaluation plan as opposed to restricting the placement of external operations to the “access level” of plans. It would, for example, be possible to make our system execute a completely new relational join method, if somebody finds a new join method which is worth-while implementing. Because our system is written in Java, it is highly portable and could be used by data, function and cycle providers with almost no effort. Furthermore, our query engine is, of course, completely distributed providing all the required infrastructure for server-server communication, name services, etc.

Extending the ODMG object model with composite objects

In this paper we extend the ODMG object data model with composite objects. A composite object is an object built by aggregating other component objects. Exclusiveness and dependency constraints, as well as referential integrity, can be associated with composition relationships among objects. Our composite object model is developed in the framework of the ODMG object database standard data model, but can be used in both object-oriented and object-relational database systems. In the paper, we propose a language for defining composite objects and we define the semantics of update operations on composite objects.

Enhanced abstract data types in object-relational databases

The explosion in complex multimedia content makes it crucial for database systems to support such data efficiently. This paper argues that the “blackbox” ADTs used in current object-relational systems inhibit their performance, thereby limiting their use in emerging applications. Instead, the next generation of object-relational database systems should be based on enhanced abstract data type (E-ADT) technology. An (E-ADT) can expose the semantics of its methods to the database system, thereby permitting advanced query optimizations. Fundamental architectural changes are required to build a database system with E-ADTs; the added functionality should not compromise the modularity of data types and the extensibility of the type system. The implementation issues have been explored through the development of E-ADTs in Predator. Initial performance results demonstrate an order of magnitude in performance improvements.

Object-relational database systems (tutorial)

Object-relational database systems, a.k.a. “universal servers,” are emerging as the next major generation of commercial database system technology. Products from relational DBMS vendors including IBM, Informix, Oracle, UniSQL, and others, include object-relational features today, and all of the major vendors appear to be on course to delivering full object-relational support in their products over the next few years. In addition, the SQL3 standard is rapidly solidifying in this area. The goal of this tutorial is to explain what the key features are of object-relational database systems, review what today's products provide, and then look ahead to where these systems are heading. The presentation will be aimed at general SIGMOD audience, and should therefore be appropriate for users, practitioners, and/or researchers who want to learn about object-relational database systems.

The BUCKY object-relational benchmark

According to various trade journals and corporate marketing machines, we are now on the verge of a revolution—the object-relational database revolution. Since we believe that no one should face a revolution without appropriate armaments, this paper presents BUCKY, a new benchmark for object-relational database systems. BUCKY is a query-oriented benchmark that tests many of the key features offered by object-relational systems, including row types and inheritance, references and path expressions, sets of atomic values and of references, methods and late binding, and user-defined abstract data types and their methods. To test the maturity of object-relational technology relative to relational technology, we provide both an object-relational version of BUCKY and a relational equivalent thereof (i.e., a relational BUCKY simulation). Finally, we briefly discuss the initial performance results and lessons that resulted from applying BUCKY to one of the early object-relational database system products.