Link field

Link fields are available for link types with the 1:1, n:1, and m:1 cardinality. You can only use link fields with 1:n and m:1 cardinalities on the link side that is limited to one data record. For the 1:n cardinality, the corresponding link side is the target data record type. For the m:1 cardinality, the corresponding link side is the source data record type.

In the example, you can see a linked and filled out database field in editing mode.