In keeping with our philosophy of designing products that can expand and grow with the minimum of effort on the part of our customers, we have adopted a strategy of making some of our products "network-capable". This means that these products can be converted from single-user mode to multi-user mode without any product upgrades or difficult configuration procedures.

As there is a variety of way in which a networked configuration can be implemented, a quick overview of the more common configurations in given below.

Whereas single-user applications typically access the underlying database directly, an application in a client/server implementation passes all requests to retrieve and store information to an intermediate software application called a "Server", or Database Server. In this type of implementation the user applications are called "Clients".

The server "serves up" the data as requested by each client application and writes information back to the relevant database when instructed to do so by the client application.

Because all communications between the client and the database must be evaluated by the server application, the performance of the overall system is slower than it would be with a direct file access approach. However, this is compensated for by the flexibility that the client/server model provides. In addition, network security is enhanced because user access can be more strictly controlled and commnications between client applications and the server can be encrypted.

The databases typically reside on a server PC and are accessed through a local area network. Alternatively, the network could be an intranet, or the internet, allowing the databases to be accessed from remote locations or by travelling sales personnel.

In summary, the client/server design allows multiple instances of an application to access the same database, or different databases, at the same time and the client applications don't need to know where the database is located - they just need to be capable of accessing the server.

A variation of the Client/Server model is often used when an organisation cannot justify the expense of a dedicated server PC. This is called a "peer-to-peer" network and the overall structure is as shown in the diagram. This is essentially the same as the Client/Server approach except that the server PC also functions as a workstation. In this case it would be normal to host the databases and server software on a separate logical or physical disk drive for security reasons, although this is not strictly necessary. In all other respects, this configuration works in exactly the same manner as a classic client/server configuration, with the same advantages and disadvantages.

For local area networks, an alternative to the client/server configuration is the "Local Mode" configuration. In this case, each application has direct access to the database, just as in single-user mode.

To implement this configuration each client application is set up to operate in Local Mode, using the Network Settings function in the client application. In addition, "connection files" must be installed which tell the application where the company databases are located.

The advantage of this approach is that the overall system performance is faster. However, it is more difficult to set up and maintain and the ability to encrypt communications and control user access centrally is lost.

When the improved performance of a Local Mode configuration is desired, and remote access is also required, a combination of the Client/Server and Local Mode configurations can be implemented. In this situation, remote users are routed through the Server and the access control and encryption features of the Client/Server model are applied. Local users access the databases directly with no encryption and the Server is bypassed. All of the record locking and transaction control features are implemented as normal.

This gives the advantage of increased speed for local users while ensuring that access to the databases over public networks is subject to additional security checks and is encrypted.

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