Library lookups exist through Cartegraph. For example City and Street are common library lookups from the Asset recordset. Creating a lookup enables you to use data that is stored in a library (such as Streets) from anywhere in the Cartegraph system. When you need more values, you add them in one place and they are available wherever you have placed the lookup field.
You can create your own lookup to an existing library or to a new library. If there is a need to look up to an existing library from a recordset, refer to the Create a Lookup Field help topic. If the library does not exist, then first refer to the Create a Library help topic.
In order for a library to be used in a lookup, one field in the library needs to be marked as unique and required. This is the primary field for the library. For example, in the Activities library, the Activity field is the primary field and is marked as unique and required. Only one field per library may be marked as unique and required.
To prevent a user from creating a lookup to a library that doesn't have a field marked as unique and require, libraries that do not have a field marked unique and required will not show in the Lookup Source Target screen.