Multimedia Databases and Servers

The Relational Model first came into vogue in the early 1980's. It was based on the simplifying idea that all data could be modeled as mathematical relations (tables in "normal form"). Permissible operations on this table data structure were specified by the relation algebra and calculus. The Relational Model led to years of research in areas such as query languages, query optimization, transaction models, and database design methodologies. This research has dominated DBMS conferences for the last fifteen years and has also lead to major products offerings in wide-spread use in the computer industry today.While the Relational revolution was happening in the DBMS community there was a minority opinion emerging from the object community. This minority opinion surfaced in heated debates and panels at DBMS conferences where it was often pitted against "relational purists." The object proponents wanted to discuss storing and retrieving complex objects and relationships in databases while the relational purists insisted on maintaining "mathematical purity and simplicity". These panels were often some of the most acrimonious (and entertaining) at these conferences and many thought there was no way to bridge the chasm between the two schools of thought.However times changes and so do the realities of the commercial world. Object languages such as C++, Smalltalk, and Java have become de facto standards. The Internet and the PC have increased the demand for complex data types. And the relational model is evolving to accommodate these realities.All of the major RDBMS vendors have announced plans for, or are already shipping, Object-Relational DBMS (ORDBMS) products. A natural question for the object community is how well these new products will address the well-known "impedance mismatch" between a pure object model and the relational model. For example, how does one make Java, Smalltalk, or C++ objects persist using an ORDBMS? Can one search for these objects in the database using their methods?The vendors for ORDBMS are claiming well-known OO features in their implementations, such as extensible data types, inheritance, object identity, and object language bindings. This panel will allow the major vendors to explain how those features match up with the kinds of object models that OO developers are accustomed to. The panel will consist of representatives from three of the major ORDBMS vendors as well as a representative of "pure object think". The vendor representatives will each present a brief overview of the object-related features of their products and will explain why OO programmers are going to have an easier time with these ORDBMSs. This will be followed by counterpoint discussion from the pure object thinker.

As part of a large effort evaluating the effect of the Exxon Valdez oil spill, we are using the spatial selection features of an object-relational database management system to support the visualization of the ecological data. The effort, called the Sound Ecosystem Assessment project (SEA), is collecting and analyzing oceanographic and biological data from Prince William Sound in Alaska. To support visualization of the SEA data we are building a data management system which includes a spatial index over a bounding polygon for all of the datasets which are collected. In addition to other selection criteria the prototype provides several methods for selecting data within an arbitrary region. This case study presents the requirements and the implementation for the application prototype which combines visualization and database technology. The spatial indexing features of the Illustra(tm) object-relational database management system are linked with the visualization capabilities of AVS to create an interactive environment for analysis of SEA data.

The relational data model is the dominant paradigm in the commercial database market today, and it has been for several years. However, there have been challenges to the model over the years, and they have influenced its evolution and that of database technology. The object-oriented revolution that got started in programming languages arrived to the database area in the form of a brand new data model. The relational model managed not only to survive the newcomer but to continue becoming a dominant force, transformed into the object-relational model (also called extended relational, or universal) and relegating object-oriented databases to a niche product. Although this market has many nontechnical aspects, there are certainly important technical differences among the mentioned data models. In this article I describe the basic components of the relational, object-oriented, and object-relational data models. I do not, however, discuss query language, implementation, or system issues. A basic comparison is given and then future trends are discussed.

Unlike conventional text-based information, media objects such as audio, video, images, graphics, are much larger in size. The recent proliferation of World-Wide Web multimedia compound documents on the Internet has resulted in ever escalating network traffic, whose rate will not be sustainable for long before encountering serious performance problems. We have devised an integrated framework covering aspects of both data storage and data distribution of multimedia objects. Our approach uses a market-based economic model incorporating four economic paradigms (i.e. client-consultant, landlord-tenant, carrier-passenger, and franchisor-franchisee paradigms) to handle policies of data caching, replication and migration. Our approach is novel in that: (1) it provides an automatic way for managing multimedia objects in a decentralized fashion, and (2) it is object-centric and thus allows providers and users of objects to contribute to the object distribution policies using the same market pricing mechanisms that also govern storage and distribution of the multimedia objects themselves.

We present our prototype system, OMCAT, which optimizes the reevaluation of a set of pending continuous spatio-temporal queries on trajectory data, when some of the trajectories are affected by traffic abnormalities reported. The key observation that motivates OMCAT is that an abnormality in a given geographical region may cause changes to the answers of queries pertaining to future portions of affected trajectories. We investigate the sources of context-switching costs at various levels and propose solutions that utilize the correlation of several context dimensions to orchestrate the reevaluation of the queries. OMCAT, fully implemented on top of an existing Object Relational Database Management System - Oracle 9i, demonstrates that our techniques can substantially reduce the response time during query answer update.

Large image databases have been designed and used in various applications and in content-based retrieval systems. Medical Imaging modalities have been developed in the past each uniquely designed to specific imaging modality based on the image pathobiological medium. This paper presents an approach to improve the process of image storage and retrieval based on image data representation model that integrates both metadata and content description. The low level features and the labels associated with the salient objects extracted from the mages are stored in an ORDBMS (Object Relational Database Management systems) using Oracle. Our technique, which combines the image descriptors obtained by a unified approach phases of image segmentation and annotation, has a good time complexity and the experimental results on several image datasets.

On the development of the database currently has become a very important thing, each will plan something, consider any thing we will need and use existing data in a database, The development of the database currently has become a very important thing, when we want to plan something and consider everything, we will need and use existing data in a database, PostgreSQL is one Object Relational Database Management Systems (DBMS) open source with a lot of features that are not less sophisticated to commercial databases. On daily use, it sometimes occurs a case that requires a dynamic column, therefore we should make the new columns to meet those needs. However, if each row of the table column requires different column and potentially need another ones, then it is going to be useless. On the research of utilizing the technology of JavaScript Object Notation (JSON),Json_encode PHP programming language can simplify the use of the column so that a new column is no longer needed when we want to create a new column on the table, we only need a new column that stores an array that has been converted into a JSON string forms the result of json_encode that represents the column name and the content of the columns of a table.

Chapter 4.2 - Perspective: Geographical Information Systems

SummaryOSD+s are enhanced object‐based storage devices (OSDs) able to deal with both data and metadata operations via data and directory objects, respectively. So far, we have focused on designing and implementing efficient directory objects in OSD+s. This paper, however, presents our work on also supporting data objects and describes how the coexistence of both kinds of objects in each OSD+ is profited to efficiently implement data objects and to speed up some common file operations. We compare our OSD+‐based Fusion Parallel File System (FPFS) with Lustre and OrangeFS through different microbenchmarks and HPCS‐IO scenarios. Results show that FPFS provides a throughput up to 37× better than Lustre and up to 95× better than OrangeFS for metadata workloads. FPFS also provides 34% more bandwidth than OrangeFS for data workloads and competes with Lustre in data writes. Results also show serious scalability problems in Lustre and OrangeFS that limit their performance.

Object-oriented models have rapidly become the model of choice for programming most new computer applications. Since most application programs need to deal with persistent data, adding persistence to objects is essential to making object-oriented applications useful in practice. There are three classes of solutions for implementing persistence in object-oriented applications: the gateway-based object persistence approach, which involves adding object-oriented programming access to persistent data stored using traditional non-object-oriented data stores, the object-relational database management system (DBMS) approach, which involves enhancing the extremely popular relational data model by adding object-oriented modeling features, and the object-oriented DBMS approach (also called the persistent programming language approach), which involves adding persistence support to objects in an object-oriented programming language. In this paper, we describe the major characteristics and requirements of object-oriented applications and how they may affect the choice of a system and method for making objects persistent in that application. We discuss the user and programming interfaces provided by various products and tools for object-oriented applications that create and manipulate persistent objects. In addition, we describe the pros and cons of choosing a particular mechanism for making objects persistent, including implementation requirements and limitations imposed by each of the three approaches to object persistence previously mentioned. Given that several object-oriented applications might need to share the same data, we describe how such applications can interoperate with each other. Finally, we describe the problems and solutions of how object-oriented applications can coexist with non-object-oriented (legacy) applications that access the same data.

Materialized view is like a cache that resembles like tables or partitioned tables and behaves like indexes and it is used for improving query performance. All of the views cannot be materialized since for any changes to the base tables it incurs huge maintenance cost but materialized views need to be updated periodically with minimum cost for efficient maintenance in a large database or data warehouse environment. So it is necessary to determine the circumstances in which a view is beneficial to be materialized for improving query performance considering the incremental materialized view maintenance cost. In this paper, we have developed a methodology that determines the circumstances a view is beneficial for selecting to be materialized considering the incremental materialized view maintenance cost in object-relational database management system (ORDBMS).

A point-set-based approximation for areal objects: A case study of representing localities

In the BlueView project, digital library services are developed and partially implemented based on the architecture of virtual document servers. Using standard tools like full-text databases or information retrieval systems, object-relational database management systems, and replication and caching services, different heterogeneous local document servers have been integrated into one virtual server. Access to heterogeneous local systems can now be performed via a single query interface, integrating features of database query systems and information retrieval or search services. BlueView distributed query processing allows for combining structured queries against meta data with content-based (text retrieval) queries against full-text collections. Legacy systems such as existing preprint servers, search engines, or meta data (catalog) systems can also be integrated. Meta data and full-text documents can be replicated within this distributed architecture. In particular, in the view of members of a certain university, metadata and documents can be replicated to a local document server and integrated under different local user views. Aspects such as terms and conditions, licenses, diverse versions of documents, different formats, and data structures are considered as well. As application scenarios, preprint servers in Mathematics and the ACM SIGMOD Anthology as local document servers have been integrated into a virtual document server.

In this paper, we discuss some design principles that will aid in the design and querying of multimedia databases. We use an object-relational data model and argue that multimedia objects should normally have a special attribute called ‘core’ which stores the real object itself in contrast to the abstraction which is reflected in the rest of the attributes. We present an extension to the ER Diagram that takes advantage of the ‘core’ notion to facilitate design of multimedia databases. We discuss some desirable features in a query language for multimedia databases: simplifications like the use of path expressions and implicit use of functions (methods) as attributes, and explicit specification of the display layout and format either at the data definition level or query specification level. To materialize this last feature, we propose a display specification extension to SQL (SQL+D) that we have implemented.

A view mechanism can provide a user with an appropriate portion of a database through data filtering and aggregation. Views are often materialized for query performance improvement, and in that case, their consistency needs to be maintained against updates of the underlying data. They can be either recomputed or incrementally refreshed by reflecting only the relevant updates. With the emergence of XML as the standard for data exchange on the Web, active research is under way on efficient storing and querying of XML documents with the DBMS. In this paper, we investigate the materialization of XML views and their incremental refresh for the case of a restricted class of views. The object-relational DBMS is employed to store XML documents and their materialized views, and the update log is used for deferred view refresh. Algorithms for checking a logged update's relevance to a view and for generating the optimized SQL statements to refresh the materialized view stored in an object-relational database through scanning of the update log are described. Experimental results show that our approach can be very effective in providing views of a large-scale XML warehouse on the Web.