INFO 232 -CH4

ERDs depict database’s main components_________

• Entities

• ALL OF THE ABOVE

• Attributes

• Relationships

__________ entity is represented by rectangle with entity’s name.

Entity name, a noun, written in capital letters.

• BOTH

• Chen

• Crow’s Foot models

___________ attributes represented by ovals

• Chen notation

• Crow’s Foot notation

___________ attributes written in attribute box below entity rectangle

• Chen notation

• Crow’s Foot notation

__________must have a value.

• Domain

• Identifiers

  (Primary Keys)

• Required attribute

• Optional attribute

__________may be left empty

• Domain

• Identifiers

  (Primary Keys)

• Required attribute

• Optional attribute

__________set of possible values for an attribute

• Domain

• Identifiers

  (Primary Keys)

• Required attribute

• Optional attribute

__________one or more attributes that uniquely identify each entity instance.

• Domain

• Identifiers

  (Primary Keys)

• Required attribute

• Optional attribute

__________ primary key composed of more than one attribute.

• Domain

• Identifiers

  (Primary Keys)

• Composite identifier

• Optional attribute

• Composite attribute

• attribute