Databases Reference
In-Depth Information
Table 1: RDB, OODB, and VWDB -A comparison-
description language such as VRML or a tool kit such as World Tool Kit. However,
VR systems have no database functions.
The idea of integrating a VR system and a database system occurred quite
naturally because it seemed that such an integrated system could inherit both the
VR capability and the database capability so that it could provide a set of all
necessary functions to describe a variety of database-based cyberspace applications.
We call this a “Virtual World Database System” (VWDB in short). By using a
VWDB, a customer can construct a three-dimensional (3-D) virtual shopping mall
with database functions so that the customer can view merchandise such as
television sets and refrigerators; moreover, the customer can ask about the price
by voice, determine how to operate a door by hand, or even see through structure.
Table 1 depicts various features of the VWDB compared with those of the two
traditional database systems, i.e., the relational database systems and the object-
oriented database systems. This table also suggests future areas of inquiry that
should be pursued in order that a virtual world database system (VWDB) may be
realized. The differences are clear, and we believe that the VWDB will be widely
used in the 21st century to develop advanced database applications.
The VWDB project was launched in April 1999 and was influenced by some of
the previous work done in the “Block World Database System” (BWDB)
development [1, 2]. As for related works, we would like to point out the study
conducted by Tanaka et al. [3] in which a realization of LoD (level of detail)-based
query capability in a VRML space was reproted, and the study conducted by
Arisawa et al. [4] in which a spatio-temporal query capability in 3-D video databases
was realized for the ergonomic analysis of human motion. However, to date, there
has been no research reported regarding the integration of a VR system and a
database system.
The rest of this paper is described as follows. The fundamental architecture of
the VWDB is described in section 2. In section 3, we give an overview of a VWDB
