Remote Data Access
Data is usually stored in databases and accessed locally (from the computer where the database management system is running, or from a computer placed in the same network with the database server). Remote Data Access refers to ways of accessing data from remote locations, over a wide area network (like the Internet).
There are several methods of using remote data, but the most promising one seems to be using Web Services. A simple example of data access through web services looks like this:
Web services are a great technology for remote data access because it masks the real database management system (DBMS) and may provide a new layer of security.
When developing applications for a specific type of DBMS, it may prove difficult to make that application run on a different DBMS. This is especially true if there are many application modules that need to be converted. In addition, if the new DBMS provides new functions that may make the application run faster, it is usually very hard to integrate them because of the old application?s coding style.
With web services acting as an intermediate layer, the applications will always communicate with the web service, without a direct interaction with the DBMS. When switching to a new DBMS, only the web service must be able to communicate with it. The applications will automatically be running, without any change.
When it comes to ?secure data access?, web services may improve security, by adding a new authentication procedure. The user is not authenticating directly to the DBMS. He must pass first through the web service. Also, by running inside a web server, the web service can be accessed from any location, without exposing to the internet new ports. Only the standard HTTP (Hyper Text Transfer Protocol) or HTTPS (Hyper Text Transfer Protocol Secure) ports need to be open to the outside world. Through the use of HTTPS, all communication between the client application and the web service is automatically encrypted.