Describe at least three E-R structures and their relational representation

What will be an ideal response?

• Regular entity: Create a relation with primary key and nonkey attributes.
• Weak entity: Create a relation with a composite primary key (which includes the primary key of the entity on which this weak entity depends) and nonkey attributes.
• Binary or unary 1:1 relationship: Place the primary key of either entity in the relation for the other entity or do this for both entities.
• Binary 1:N relationship: Place the primary key of the entity on the one side of the relationship as a foreign key in the relation for the entity on the many side.
• Binary or unary M:N relationship or associative entity: Create a relation with a composite primary key using the primary keys of the related entities, plus any nonkey attributes associative entity of the relationship or associative entity.
• Binary or unary M:N relationship or associative entity with additional key(s): Create a relation with a composite primary key using the primary keys of the related entities and additional primary key attributes associated with the relationship or associative entity, plus any nonkey attributes of the relationship or associative entity.
• Binary or unary M:N relationship or associative entity with its own key: Create a relation with the primary key associated with the relationship or associative entity, plus any nonkey attributes of the relationship or associative entity and the primary keys of the related entities (as foreign key attributes).
• Supertype/subtype: Create a relation for the superclass, which contains the primary relationship key and all nonkey attributes in common with all subclasses, plus create a separate relation for each subclass with the same primary key (with the same or local name) but with only the nonkey attributes related to that subclass.