Databases Reference
In-Depth Information
Database 10
g
, the capabilities of Real Application Clusters support deployment to a new
computing model: grid computing. But many of the capabilities that enable OLTP with
Oracle have been core to the database product for many years.
As described above, Oracle Database 12
c
extends the robustness of OLTP with Trans‐
action Guard and Application Continuity, which practically eliminate the window of
indeterminate transaction outcomes.
The remainder of this chapter examines many of these features in more depth.
Architectures for OLTP
Although all OLTP systems are oriented toward the same goals, there are several dif‐
ferent underlying system architectures that you can use for the deployment of OLTP,
including the traditional two-tier model, a three-tier model, and a centralized model
that encompasses the use of the Web and the grid.
Traditional Two-Tier Client/Server
The late 1980s saw the rise of two-tier client/server applications. In this configuration,
PCs acted as clients accessing a separate database server over a network. The client ran
both the GUI and the application logic, giving rise to the term
fat clients
. The database
server processed SQL statements and returned the requested results back to the clients.
While the database server component of these systems was relatively simple to develop
and maintain using visual tools, client components were difficult to deploy and maintain
—they required fairly high-bandwidth networks and the installation and regular up‐
grading of specific client software on every user's PC.
Figure 9-1
illustrates the two-tier architecture.
Figure 9-1. Two-tier client/server architecture
