Strong entity set and weak entity set?
Strong entity set and weak entity set: A strong entity set has a primary key. All tuples in the set are distinguishable through that key. A weak entity set has no primary key unless attributes of the strong entity set on that it depends are involved. Tuples in a weak entity set are partitioned according to their relationship along with tuples within a strong entity set. Tuples within each partition are distinguishable through a discriminator that is a set of attributes. A strong entity set has a primary key. All tuples in the set are distinguishable through that key. A weak entity set has no primary key unless attributes of the strong entity set on that it depends are included. Tuples in a weak entity set are partitioned according to their relationship along with tuples in a strong entity set. Tuples within every partition are distinguishable through a discriminator, which is a set of attributes.