Each entity should have one or more attributes which can uniquely distinguish a particular occurrence of that entity. Each distinguishing attribute or group of attributes is known as a key value. Also, for each relationship you have defined, an attribute or group of attributes should
specify the relationship by forming a link between the entities. In the case of Station Log and Selection, the links are "Selection Name" and "Selection Title." In the case of Selection and Composer, the link is "Composer Name," which is an attribute of Composer, but would need to be added to the list of attributes for Selection. In the case of Album and Selection, there is a possible link in "Album Code," which would have to be added to the list of attributes for Selection.
