Midterm Prepare

Attribute : A property of an entity or a relationship type.
Attribute Domain : The set of allowable values for one or more attributes.
Simple Attribute : An attribute composed of a single component with an independent existence.
Composite Attribute : An attribute composed of multiple components, each with an independent existence.
Single-Value Attribute : an attribute that holds a single for each occurrence of an entity type.
Multi-Value Attribute : An attribute that holds multiple values for each occurrence of and entity type.
Derived Attributes : An attribute that represents a value that is derivable from the value of a related attribute or set of attributes, not necessarily in the same entity type.
Composite Key: a candidate key that consists of two or more attributes.
Strong Entity: An entity that is not existence-dependent on some other entity type.
Weak Entity : An entity that is existence-dependent on some other entity type.
Cardinality : Describes the maximum number of possible relationship occurrences for an entity participating in a given relationship type.
Participation : Determines whether all or only some entity occurrences participate in a relationship.
Fan trap: Where a model represent a relationship between entity types, but the pathway between certain entity occurrences is ambiguous.
Chasm traps : Where a model suggests the existence of a relationship between entity types, but the pathway does not exist between certain entity occurrences.
Super Class : An entity type that includes one or more distinct sub groupings of its occurrences, which require to be represented in a data model.
Sub Class : A distinct sub grouping of occurrences of an entity type, which require to be represented in a data model.
Specialization : The process of maximizing the differences between members of an entity by identifying their distinguishing characteristics.
Generalization : The process of minimizing the differences between entities by identifying their common characteristics.
Participation Constraint: Determines whether every member in the super class must be participate as a member of a subclass.
Disjoint Constraint : Describes the relationship between members of the subclasses and indicates whether it is possible for a member of a super class to be a member of one or more than one subclass.

Aggregation : Represents a 'has-a' or 'is part of' relationship between entity types, where one represents the 'whole' and the other the 'part'.
Composition : A specific form of aggregation that is represents an association between entities, where there is a strong ownership and coincidental lifetime between the 'whole' and the 'part'.