Component Design for Relational Databases - High-Performance Web Databases: Design, Development, and Deployment - page 389

Exhibit 25-5. One-to-many component to subdata model example.
In Microsoft's DCOM technology there are two main types of compo-
nents:
1. ActiveX Exe
2. ActiveX DLL
The difference between the two types of components is that the ActiveX
Exe is an out-of-process component while the ActiveX DLL is an in-process
component. In-process components usually offer significantly better per-
formance than out-of-process components. However, in-process compo-
nents and their client applications must reside on the same physical
machines. With out-of-process components there is no such restriction,
therefore out-of-process components offer greater flexibility in terms of
deployment at the cost of application performance.
The choice between in-process and out-of-process components would
therefore depend on the physical architecture. Note that three-tier software
architectures can be deployed using two-tier physical architectures. In a
two-tier implementation, the database runs on a database server and the
user interface layer as well as the business layer runs on the client desktops.
This kind of implementation is also called fat-client, since most of the appli-
cations are deployed on individual workstations. Whereas this might be suf-