Typically, when workers in branch offices across a city, county or state need access to a master database, issues arise concerning performance and network traffic. As the number of users accessing the database rises, the time it takes to run a query can lengthen considerably. To offset this problem, database vendors have developed data replication. Considered by Davis to be still under development rather than a mature function, data replication enables copies of a database to be disbursed to different servers on a network. Any changes made to the data by users are automatically replicated, so everyone is constantly working with the same data, not different versions of it.
Data replication serves other purposes.
However, data replication has two drawbacks, according to Davis. First, to carry out replication requires a network that is always up and running, otherwise the changes made to the data can't be replicated automatically. Second, data replication is currently restricted to the vendor's database. Further along in development is the use of gateways, which allow users to access different databases transparently. The gateways translate database commands so, for example, a user on an Oracle database can use Oracle's Open Gateway Technology to send an SQL query to an Informix system located elsewhere on the network.