DP4 is based on a client/server architecture. You can configure your system to run over a network by setting up a server machine. The DP4 utilities and the database are installed on this machine, which can also be used as a workstation in its own right, and workstations access the database over the network.
Each workstation runs its own copy of the user interface manager, allowing different types of workstations to be used on the same system.
There are many possible configurations of DP4 networking. Two of the most important are:
DP4 allows you to access more than one server over a network. This means that a program can update databases in different locations. The program does not need to know how a database is distributed. The application simply makes a call to update the database, and the database manager consults a control table to discover the location of the table.
In a resilience system, a copy of the database is maintained on more than one server. Resilience systems ensure non-stop working of an application, since a failure on one of the servers does not affect the working of the second server. If a server fails, it may be off-line temporarily, but the second server continues as normal. As soon as the failed server is back on line, it can be updated with any transactions recorded on the second server during the failure.
You can find out more about DP4 networking in Resilience and Distributed Databases.