Let’s start from understanding what is an event. The dictionary explains events as “a thing that happens, of importance”. Second part, i.e. “of importance” is a bit tricky, some events can be important for one but not for another. For example clicking anywhere on your computer screen is actually an event, but it does not result into an action, but clicking on some icon is event of importance as that will open up some application. In a banking system an event will be when someone withdraws money, checks balance, closes account or open account etc. In a computer game there will other type of event like, jump, run, hit, kill, fire etc.

Event processing is what should be done when the event occurs. For example, what to do when a specific icon on a window is clicked? What should be done when an event of withdraw money occurs – check if pin/ signature is correct, check if there is sufficient balance, pay money to person, reduce the amount from balance etc.

Now next level is to handle complex events. A complex event is an event which is result of many events occurring in relation to each other forming a definite pattern.

We are receiving following information from a ground
1. A man is kicking a football.
2. There are 2 goal posts set on opposite ends of ground.
3. There are few men in the ground trying to take control of same ball.

We can deduce a complex event – a football match.

This kind of pattern detection and complex event processing is used in Operational Intelligence solutions to identify opportunities and threats. For example banks use this kind of event processing to detect and take action on fraud detection. Say if a credit card transaction seems out of place, the amount deducted is not supported by historical data about the card usage, or the card is being used too frequently or the card is used at a location which is not in proximity of the consumer address, this kind of events, combination can generate an event for “CheckCreditCardFraud” or “StopPayment” or “RaiseAlert”.