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12 Chapter 1 • Introduction to Enterprise Systems for Management

High-Level Enterprise Resource Planning System Components

Business Processes
SAP, Oracle/Peoplesoft, Great Plains Human Resources
Billing, Manufacturing

ERP
Software

Network
Local Area Network, Wide Area Network
Servers
Servers and Operating Systems
Sun/Solaris, Intel/Windows 2003/Linux

Workstation

Oracle, MS SQL, Sybase, DB2 End Users
Laptop Subject Matter Experts,
IT Staff

FIGURE 1-5 Example of Architecture of ERP at Large University

The architecture must therefore be conceived after the selection of ERP software, whereas the
architecture is conceived well before buying or developing software in other IT implementations.
An ERP package can have a very different implementation outcome from one organization
to another. In the architecture of a large university, an ERP system can be very complex and must
be designed and tested thoroughly before implementing it in the organization (Figure 1-5).
The architecture sets the stage for modifications or customizations to support an organization’s
policies and procedures, data conversion, system maintenance, upgrades, backups, security,
access, and controls. Many organizations often make the mistake of ignoring the system
architecture stage and jumping directly into ERP implementation because they have planned a
“vanilla” or “as-is” implementation. This can be disastrous because the organization will not be
prepared for long-term maintenance and upkeep of the system.
The two types of architectures for an ERP system are logical (see Figure 1-6) and physical
or tiered (see Figure 1-7). The logical architecture, shown in Figure 1-6, focuses on supporting
the requirements of the end users, whereas the physical architecture focuses on the efficiency
(cost, response time, etc.) of the system. The logical architecture provides the database schemas
of entities and relationships at the lowest tier, followed by the core business processes and
business logic handled by the system at the second tier. The third tier provides details on the
applications that support the various business functions built in to the ERP system. The end users
do not ever see the first and second tiers because they interact primarily with the client–user
interface application tier that provides them access to the functional applications.