With MicroStation CONNECT Update 4 and earlier we can define Item Types and the data type assigned to each property. What the user does when creating an Item instance from that Item Types schema is current a free-for-all: user can enter any data she likes.
It would be useful to be able to provide a pre-defined set of values that a user can choose. For example, we're considering AreaAnnotator CONNECT Edition. AreaAnnotator helps document and manage area items such as rooms or building lots, where it's useful to annotate each area with an ID and a Purpose.
Let's look at an example of space planning. An office floor will have a number of offices and other space. We want to annotate each room or space with an ID and describe what function it serves with Purpose. The ID annotation will presumably vary, so it's up to the user to provide a valid Room No.. However, the Purpose fits into a number of well-known roles — say Office, Circulation, Storage, Hallway. Right now a user can create Item data that might be a member of that set but could be deliberately different, say, Attic; or it could be inadvertently different, say, Hellway. If an administrator could pre-define a list of valid Purpose values that problem is solved.