I'm going to build an outdoor table with cedar. Something similar to
Size of the table top will be about 3'x6'
The legs will be 4x4s and rails will be 2x4s. Table top will be 2x6s with 1/4" gap between boards.
Will the pocket hole connection strong enough to connect the rails to the legs?
I would think 3 pockets in the rail would be adequate. Since you are attaching to a 4x4 your screws can be extra long.
I would suggest another method of jointery for the legs and major supporting frame work. Cedar is too soft to hold a pocket screw in the joints that hold the frame work. The pocket screw would be fine for attaching the table top to the frame. The legs to the rails are stressed too much for a butt joint made by a pocket screw.
I would consider using a mortise and tennon joint method to add strength to your basic frame. It will take some time however the rewards of a long lasting table will justify the time you spend.