An event handler is provided that associates events from heterogeneous data sources. In a first phase, incoming events are translated to vectors of event attributes. Based on the data source, implicit information about the event and its attributes may be available. This information is used to normalize the information provided by the event. Normalization actions may include renaming the attributes, deriving new attributes from given attributes, and transforming attribute value ranges. In a second phase, a determination is made as to whether two or more events are considered to be associated based on the vectors. Different vectors of core attributes may be created in order to create associations with different semantics.