When both rooms and Item have been specified in detail, the correlation between these specifications can be checked by defining a set of rules. When an Item is entered for a room and this is governed by constructional requirements, the rules set up can check whether the room data sheet for this room meets the requirements. Say that 3 computers are to be placed in a room and all require power supply. If only 2 sockets have been set up in the room, then there is a probable error. If 30 sockets are set up in the room, and no other item in the room requires power, this is also a probable error. This is an example of a resource in the room you want to include, but other rules are also possible; for example, certain types of item may require a minimum/maximum temperature in the room in order to function properly, or require noise insulation as the item generates a lot of noise.
The set-up of rules can be complex and is normally carried out by the project administrator.