Object Database Management System Research Articles

Využití návrhového vzoru adaptér pro odstínění rozdílů v API objektových databází

Actual ERP systems use for data storage mainly relational databases, but in specific situations, particularly for modeling complex relationships can also use the object databases. These information systems are usually developed using object-oriented programming languages like C++, Java, C #, and it would seem natural that for the data storage they also use the object-oriented databases instead of the relational databases, thus dispensing with the need for mapping objects into relations. But this is not true especially because of two reasons. The first reason is historical and the resulting enormous widespread of the relational databases, which were here before the object-oriented databases. The second reason for minority use of the object-oriented databases is the minimum compliance of standards by the object DBMS (Database Management System) producers, such as SQL standard in relational databases, resulting in differences in the API (Application Programming Interface) of object-oriented DBMS and the impossibility to change the object-oriented DBMS in an application without having to rewrite the code of an entire application which is built on that object-oriented database. The following paper attempts to resolve this issue.

Integrated Information System of Balaod Mindanaw Incorporated

Integrated Information System of Balaod Mindanaw Incorporated is designed and developed to facilitate the following areas of operation: profiling of employees, monitoring of library resources, preparation of payroll, requisition and inventory of supplies, and preparation and monitoring of budget. Each system incorporates a common object database management system. Compared to the company’s current system, the LAN- based system helps minimize user error and is time-saving, hence a better option for facilitating transactions. Also, it is much easier to use since the interface is user-friendly. The system is locally networked and is operated by one server that updates all transactions into four sections. Keyword - Integrated Information, Automated

Method of adaptive controllable parallel execution of operations in object database management systems

The design of parallel database management systems (DBMSs) normally implies using special-purpose multiprocessor computing systems. Most often, a DBMS is supposed to work in an exclusive mode of operation. However, in the class of x86-based multiprocessor computing systems designed for mass usage, the exclusive mode of DBMS operation with respect to other software is often not secured. In addition, the legacy software for this class of computing systems is often not designed for mass parallel usage. When the exclusive mode requirement is ignored and the resources of the computing system are not used in low-load DBMS regimes, the efficiency of using resources of the computing system as a whole reduces. This paper considers a method of program organization of controlled parallelism at the level of internal DBMS operations, allowing for their controlled execution based on the state of the entire computing system. This method made it possible to significantly reduce the time of response for low densities of query arrival in the ODB-Jupiter commercial object DBMS developed in the Inteltec Plus scientific manufacturing center. The method of controlled parallel execution can be used in a wide class of program systems.

An Adaptive Data-Shipping Architecture for Client Caching Data Management Systems

Data-shipping is an important form of data distribution architecture where data objects are retrieved from the server, and are cached and operated upon at the client nodes. This architecture reduces network latency and increases resource utilization at the client. Object database management systems (ODBMS), file-systems, mobile data management systems, multi-tiered Web-server systems and hybrid query-shipping/data-shipping architectures all use some variant of the data-shipping. Despite a decade of research, there is still a lack of consensus amongst the proponents of ODBMSs as to the type of data shipping architectures and algorithms that should be used. The absence of both robust (with respect to performance) algorithms, and a comprehensive performance study comparing the competing algorithms are the key reasons for this lack of agreement. In this paper we address both of these problems. We first present an adaptive data-shipping architecture which utilizes adaptive data transfer, cache consistency and recovery algorithms to improve the robustness (with respect to performance) of a data-shipping ODBMS. We then present a comprehensive performance study which evaluates the competing client-server architectures and algorithms. The study verifies the robustness of the new adaptive data-shipping architecture, provides new insights into the performance of the different competing algorithms, and helps to overturn some existing notions about some of the algorithms.

A study of object declustering strategies in parallel temporal object database systems

In a transaction-time temporal object database management system (TODBMS), updating an object creates a new version of the object, but the old version is still accessible. A TODBMS will store large amounts of data, and in order to provide the necessary computing power and data bandwidth, a parallel system based on a shared-nothing architecture is necessary. In order to benefit from a parallel architecture, a suitable declustering of the objects over the nodes in the system is important. In this paper, we study three low-cost declustering algorithms: (1) declustering based on the hash value of the OID of the objects, (2) range partitioning based on the timestamp of the objects, and (3) a new hybrid algorithm, where current object versions are declustered according to the hash value of the OID, and the historical versions are range partitioned based on timestamp. In contrast to many similar studies, we study the performance with a workload including both read and update operations. We show that strategies 1 and 3 are the most scalable strategies, and that the new hybrid declustering strategy is especially suitable for low update rates, for example in geographical information systems and decision support systems with support for temporal data. However, in general declustering based on the hash value of the OID of the objects has the most stable and predictable performance.

The COMPASS off-line system

COMPASS is a new fixed target high rate experiment at CERN. The expected RAW data size is in the order of 300 TB per year, collected during about six months of data taking at the mean rate of 35 MB/s. To fulfill the experiment requirements, the Collaboration decided to build the off-line system using new technologies. The computing power needed for RAW data processing has been estimated to be in the order of 2000 SPECint95, and will be provided by a farm of about 200 CPUs. The reconstruction program is under development and is written using object-oriented techniques and C++ as the programming language. In the present model, all the experimental and reconstructed data will be stored in an object database management system.

Agricultural enterprise information management using object databases, Java, and CORBA

A software architecture based on an object database management system (ODBMS), Java, and Common Object Request Broker Architecture (CORBA) was applied to a variety of agricultural enterprise applications. The advantages and disadvantages of using object database are compared with conventional relational database management systems in complex applications. In a distributed object computing environment, a commercial ODBMS provides a repository for information on agriculture and natural resources in large organizations, Java provides a high-level programming environment, and CORBA provides a way of sharing applications and information across the Internet. Several applications are described, including an extension publication archive and an institutional accountability project. Results were that the object database offered significant advantages in modeling complex data applications, and the object design approach led to an overall increase in productivity by software developers. However, the technology in general suffers from a lack of maturity.

Index set: A practical indexing scheme for object database systems

Efficient indexing in a class hierarchy is essential for the achievement of high performance in query evaluation for object database management systems. In this paper, we present a practical indexing scheme, index set, which provides good index configuration for any real database environment. The proposed scheme considers the distribution of key values, as well as query patterns such as query weight on each class. The index set can easily be applied to any database system, since it uses the well-known B +-tree structure. We develop a cost model and, through experiments, demonstrate the performance of the proposed scheme over various class hierarchies.

Secure object deletion and garbage collection in multilevel object bases1

This paper introduces guidelines aiming at the prevention of illegal information flows due to object deletion in multilevel secure object database management systems (ODBMSs). Although a delete operation can be viewed as a kind of write operation, this does not suffice to avoid covert channels. Hence, the attention is focused on delete operation and its implications on database security. The guidelines we propose are formally stated as security principles. We also show how to design a garbage collection mechanism in a multilevel secure ODBMS. The garbage collection mechanism ensures both security and referential integrity.

A performance study of Object Database Management Systems

Vendors of Object Database Management Systems (ODBMSs) have used a number of different architectural approaches for their products. Generally, most previously published ODBMS performance work focused on engineering applications and very little known about the suitability of ODBMS implementations for other application domains. In this paper, we redress this imbalance and evaluate three commercial products (two pure ODBMSs and one hybrid Object-Relational DBMS) to determine the suitability of each for six different application domains. Our results show statistically significant performance differences between the products under test. Furthermore, the hybrid product consistently performed badly on most of our tests. We also found that testing the scalability of products in terms of database size, as well as the choice of language interface, can be very important. Furthermore, the use of a dedicated database load utility can save considerable time when loading simple data, but generating complex data for the load utility requires considerable manual intervention. © 1999 John Wiley & Sons, Inc.

Representation of standard mechanical components in a STEP-based product data management system

A product data management system, PDMS, stores and manages complete information about all its products and related activities. With proper management of such information, product development can be made easier and more efficient. Together with widespread computer network applications, PDMS enables an enterprise to exercise its business activities in a more efficient way. However, the standard representation of product data and their communication are two major obstacles to be overcome. In this paper, we present a set of procedures to represent a standard mechanical component and propose a method for the data management and its communication within the PDMS. The Standard for the Exchange of Product Model Data, STEP, is used for the data representation. The object database management system, ODBMS, is used for the data management because of the object-oriented nature developed by STEP. The open database connectivity, ODBC, server is also introduced for connecting different databases on the network. With the proposed procedure and architecture, we demonstrate the way to implement STEP and the way to merge the object-oriented modelled data in the PDMS. As STEP matures and computer networks get faster and more popular, the networked PDMS will be a must for future enterprises.

A new architecture for integration of CORBA and OODB

Object oriented database system (OODB) supports an object oriented data model with the functionality of persistency and transaction semantics. In order to facilitate the use of OODB, the Object Database Management Group (ODMG) defined a standard for object database management systems. On the other hand, the Object Management Group (OMG) defined the Common Object Request Broker Architecture (CORBA), which is an emerging standard of distributed object technology providing the interconnection network between distributed objects. For the sake of matching these two object models, taking the advantages of merging both of them, and building a more sophisticated infrastructure, the integration of CORBA and OODB is currently an urgent and important issue in distributed object systems. Instead of using Object Database Adapter (ODA) suggested by the ODMG, we provide a novel way of reusing the Object Transaction Service (OTS) and wrapping techniques to introduce OODB into CORBA automatically. Through our design, CORBA clients or OODB object implementers do not need to learn any knowledge of each other. In addition, error recovery is also provided to guarantee the consistency of object states. The whole task for integrating CORBA and OODB is done transparently by our proposed preprocessor, which plays an important role in solving problems encountered by ORB and OODB vendors easily.

A temporal approach to managing schema evolution in object database systems

The issues of schema evolution and temporal object models are generally considered to be orthogonal and are handled independently. However, to properly model applications that need incremental design and experimentation, the evolutionary histories of the schema objects should be traceable rather than corrective so that historical queries can be supported. In this paper we propose a method for managing schema changes, and propagating these changes to object instances by exploiting the functionality of a temporal object model. The result is a uniform treatment of schema evolution and temporal support for many object database management systems applications that require both.

Modeling medical trials in pharmacoeconomics using a temporal object model

Time is an inherent feature of many medical applications. These applications can also benefit from the support of object database management systems which better capture the semantics of the complex objects that arise in the medical domain. In this paper, we present a uniform behavioral temporal object model which includes a rich and extensible set of types and behaviors to support the various features of a medical application. We concentrate here on the application of pharmacoeconomic medical trials. Pharmacoeconomics is a field of medical economics in which the costs and outcomes of alternative treatments are assessed and compared, in order to establish which is the most appropriate treatment for a particular illness in a particular setting. We describe in detail the histories and timelines features of our temporal model and show how they can effectively be used to model a pharmacoeconomic trial. We then give an instance of a pharmacoeconomic trial as it would appear in the temporal object model and show, using queries, how a series of different behaviors could be used to retrieve various components of the instance. These components could then be used to assess the alternative treatments involved in the trial and determine their cost-effectiveness.

A fine-grained process modelling experiment at British Airways

We report on the experimental application of process technology that we did at British Airways (BA) as part of the GOODSTEP project. The goal of GOODSTEP was to enhance and improve the functionality of an object database management system (ODBMS) to yield a platform suited to the construction of process-centred software engineering environments (PSEEs). These enhancements were exploited and validated by the construction of the GOODSTEP framework for PSEE construction, which includes the SPADE software process toolset. We used the process modelling language SLANG to model BA’s C++ class library management process, and we constructed an experimental PSEE based on SPADE. BA required processes to be automated at a finer degree of granularity than that of tool invocation. We have demonstrated that SLANG and SPADE offer the basic mechanisms for modelling these fine-grained processes. We have also shown that it is feasible to generate tools for dedicated processes and integrate them within a SLANG model so as to facilitate fine-grained process automation. However, our experience highlighted some open problems. For instance, SLANG process models are tuned to efficient enactment, thus containing very detailed process fragments. These are not the most appropriate representations for humans trying to understand the process model. Although the airline did not deploy the PSEE in its production environment, the experiment proved beneficial for BA because the modelling activity itself uncovered serious flaws in the existing process. © 1997 John Wiley & Sons, Ltd.

Evaluating object DBMSs for multimedia

We describe functionality for determining an object database management system's suitability for developing multimedia applications. We discuss all levels of hardware and software support, as even the most ideal database software cannot operate independent of operating systems, networks and hardware. A review of the multimedia support provided by current commercial and research object database management systems is also included.

Tool construction for the British Airways SEE with the O2 ODBMS

Software engineering environments (SEE) support the construction and maintenance of large-scale software systems. They integrate tools for the production and maintenance of documents such as requirements definitions, architecture definitions or user manuals. Very few SEE tools meet all the developers' requirements. Some requirements that are important in practice have not been appropriately addressed. These are inter-document consistency handling, version and configuration management and cooperative work. We claim that the reason for current tools not meeting these requirements is the fact that the required database support for maintaining documents is only now becoming available. The British Airways SEE meets these new requirements. Its tools were constructed using the O2 object database management system, which has been extended to become a database management system for software engineering. We discuss the experiences we made during tool construction for this SEE.

Managing Information in a Co‐operative Object Database System

The paper describes a software infrastructure that was built to manage information in a co-operative environment for the design of control systems. The architecture of the environment, the organization of the design database and a suite of information management tools are presented. The paper suggests that the distributed client-server architecture and object database technology meet the requirements of managing information in the environment. The following issues related to information management are examined in more detail: support for version control, maintenance of information integrity by means of object access control and consistency control, support for user co-operation based on object sharing and change notification, graphical user interfaces, and design tool interfaces. Problems encountered during the implementation of the environment using a commercial object database management system are also discussed.

A comparison of ORN to other declarative schemes for specifying relationship semantics

Object Relationship Notation (ORN) allows relationship semantics to be specified to an object database management system (ODBMS) when relationships are represented as object-valued class attributes, both singly and multiply valued. Other declarative schemes have been proposed or developed to define semantics for such relationships when they are represented as foreign keys in a relational database or as relations in an extended object data model. In this paper we give an overview of ORN and compare it to these other schemes as well as to the declarative capabilities that currently exist for defining relationships in commercial ODBMSs. The purpose of our comparison is to permit the relative merits of ORN to be appreciated and to underscore the need for such a notation in ODBMSs.

A coherent architecture for a temporal object data base management system

The last decade has witnessed the emergence of practical general-purpose data base management systems (DBMS) as “state of the art” technology. In consequence, these systems are now widely used in a variety of application environments. However, many such systems were designed to capture current data, i.e., a snapshot of reality, but are insufficient for those applications in which past or future data are also required. Even so, there has been little effort to design temporal DBMS, and currently there are no prominent commercial temporal DBMS. This article identifies, explores, and provides an approach to designing a coherent architecture for a temporal object DBMS (TODBMS). It specifically involves the design, development, and implementation of TODBMS. We introduce the basic features of our system and provide an overview of the functionalities supported. In addition, we identify the major components of TODBMS and define the types of services each component should offer, as well as common abstractions and interfaces for these components. Application environments include management and geographic information systems, data base visualization, and robotics.