|Oracle9i Application Developer's Guide - Large Objects (LOBs)
Release 1 (9.0.1)
Part Number A88879-01
The Multimedia Schema Used for Examples in This Manual, 2 of 5
LOBs, large objects which can hold up to 4 gigabytes of binary or character data. What does this mean to you, the application developer?
Consider the following multimedia scenario.
Multimedia data is used in an increasing variety of media channels -- film, television, webpages, and CD-ROM being the most prevalent. The media experiences having to do with these different channels vary in many respects (interactivity, physical environment, the structure of information, to name a few). Despite these differences, there is often considerable similarity in the multimedia authoring process, especially with regard to assembling content.
For instance, a television station that creates complex documentaries, an advertising agency that produces advertisements for television, and a software production house that specializes in interactive games for the web could all make good use of a database management system for collecting and organizing the multimedia data. Presumably, they each have sophisticated editing software for composing these elements into their specific products, but the complexity of such projects creates a need for a pre-composition application for organizing the multimedia elements into appropriate groups.
Taking our lead from movie-making, our hypothetical application for collecting content uses the clip as its basic unit of organization. Any clip is able to include one or more of the following media types:
Since this is a pre-editing application, the precise relationship of elements within a clip (such as the synchronization of voice-over audio with a photograph) and between clips (such as the sequence of clips) is not defined.
The application should allow multiple editors working simultaneously to store, retrieve and manipulate the different kinds of multimedia data. We assume that some material is gathered from in-house databases. At the same time, it should also be possible to purchase and download data from professional services.
Our mission in this appendix is not to create this real-life application, but to describe some typical scenarios you may need to know about working with
LOBs. Consequently, we only implement the application sufficiently to demonstrate the technology. For example, we deal with only a limited number of multimedia types. We make no attempt to create the client-side applications for manipulating LOBs.
Also we do not deal with deployment issues such as the fact that you should implement disk striping of LOB files, if possible, for best performance.