In version 3.x the "ZZ" seperates the Source Context Buffer from the Destination Context Buffer.
Source Context Buffer are the characters from the source address of the alarms, and vice versa for the Destination Context Buffer.
So you really need two fields in mysql and use the "ZZ" to split the joined Context Buffer into the 2 separate Context Buffers (Source and Destination).
I am not sure what the "==" is used for in 4.0.