No, it is not correct. But neither is your ER diagram.
Where is you BOOKING table???
You seem to have subsumed it TWICE into EquipmentBooking and DJBooking. I think that's a mistake. Here, the ER diagram is right.
I don't see the primary keys in any of your tables in the ER diagram. No bookingid for example. And you use customerid in your two booking tables but you don't have customerid as a primary key in your customers table. And and and and...
Yes, you clearly need a category table.
You have no fields at all in either the DJ table or the DJBookingTable that allows them to be linked together.
I'm sorry, but both the ER and the classes need to completely reworked.
An optimist sees the glass as half full.
A pessimist sees the glass as half empty.
A realist drinks it no matter how much there is.