The most important goal of Event Driven Wireless Sensor Network (EDWSN) is to detect an event and pass this detected event to the users. Accurate event detection and fast event transmission play vital role in event detection. Many researchers have been proposed various techniques to detect events in an EDWSN. This paper describes a survey on event detection and event transmission protocols in an Event Driven Wireless Sensor Networks. We have classified these protocols into mainly two categories namely Sink Centric Event Detection and Transmission Protocols (SCEDTPs) and Node Centric Event Detection and Transmission Protocols (NCEDTPs). Then, these protocols are further classified into three categories under the constraints reliability, congestion resolution and energy efficiency. The advantages and disadvantages of each protocol also studied and we made the comparison of each protocol with different constraints.