Buy a snooper 3zero camera detector if you need to speed, detects lazer, radar and fixed cameras by satellite. It's kept me out of trouble
Better would be to stay alert, and look well ahead, and moderate the speed to the conditions. Mostly speed detection is done where situations are higher risk, or there is a history of speeding.
Lazer camera detectors will alert you if the lazer beam hits it, but the beam is quite precise so can be missed by the detector.
Radar cameras are mostly taking readings from behind you as you pass. The only radar to be detected will be that reflected to your detector from other objects. With no oncoming traffic, you may not get the warning.
Fixed camera data needs to be updated, but not such a problem as new cameras are rare.
Average speed cameras will not be seen by any detector, or be on any database, but your eyes should be enough, both for the cameras and the speedometer.