The starting point for CQL is the CQL query . A CQL query is a single statement that defines how input events are to be processed and transformed into output events.
Oracle Event Processing considers an event as a collection of named key-value pairs. This is sometimes known as tuples. Each one of these pairs defines an attribute or property of the event, so henceforth we shall refer to them as event properties . Considering this, a better definition of a CQL query is that it specifies how particular properties of the input events are processed and result into output events with their own set of properties.
Let's take a look at an example. Consider an event
e1 that contains two properties,
p2, whose values are ...