What two courses of action are available to designer encountering a multivalued attribute?
A multi-valued attribute is an attribute in an entity that can contain multiple values. This in in contrast to single-value attributes that contain a single value. An example of a multi-value attribute is the "hobbies" attribute for an "employee" entity. It is expected that an employee can have more than one hobby.
Database designers have two approaches available when dealing with multi-valued attributes. The first, and simplest approach is to simply put all of the values in a single fields, separated by a delimiter. Continuing with our "hobbies" example, we could create values like: "biking, fishing, reading" or "dining, riding". The appeal using this approach is that it is simple and requires no additional database structure. The difficulty of this approach is that it eliminates much of the power of ...
This solution explains what multi-valued attributes are and the different options for handling them in the design of a database.