entity type to the relationship, whereas partial participation is

entity type to the relationship, whereas partial participation is represented by a single line. . . Weak Entity Types Entity Types, which do not have identifier (or key attributes) of their own are, called weak entity types.

Such entity types are identified by being related to specific entities from another entity type in combination with some of their attribute values. These other entity types are called identifying or owner entity type. Accordingly, the relationship type that relates a weak entity type to its owner is called identifying relationship of the weak entity. A weak entity type always has a total participation constraint (existence dependency) with respect to its identifying relationship because it cannot be identified without its owner entity.

For example, a voucher may be accompanied by a set of support documents such as bills, issued by other parties to the transaction, details of which need be stored. Such SUPPORT’ DOCUMENT entity type which is used to keep track of support documents attached to each voucher via :N relationship, is a weak entity. This is because they are identified as distinct entities only after determining the particular voucher. A weak entity type normally