Application integration 4 December 2008, by Johnny
Enterprise systems represent large investments, and need to last a good decade to be worth the cost. So, at any one time, an enterprise has a mix of 'state of the art' systems... and systems that were 'state of the art' 15 years ago. We integrate these, and we do it using a broad range of tools.
Historically, systems have been integrated by file transfers or by direct access to databases. These are still the most common -- we have recently built systems that read flat file outputs from old systems or provide protected, secure database access to 3rd party systems.
Modern systems are often linked by offering interfaces to third party software. Often this is consuming a web service, for example, we have been integrating smart card payment systems in the transport industry. On other occasions, we've used proprietary interfaces such as RPC calls to SAP, or accessing the Sage SDO.
We recently took over and upgraded an EDI component... well! We were writing EDI systems in the 1990s when the Internet was still in short trousers. These technologies live on; it's not all apps.
Working on Enterprise systems takes a team with long experience, a big bag of tools, and a realisation that enterprise scale systems are not just large small-business systems.