represents the relationship between a SingleEntityType and the PartialEntityType that consists of only that SingleEntityType. 

an AggregateValue, representing a value of an EXPRESS ARRAY data type: a set of pairs of the form (index value, domain value) where the index value is selected from a finite range of integers, and each such value occurs in exactly one pair, and the domain value is an instance of the member-type of the ARRAY. 

a ConcreteValue that is composite, consisting of a collection of Instances from a given member DataType. 

Represents a single element of an ARRAYValue seen as a relation. 

represents the assignment of a value to a given Attribute of the EntityType corresponding to the SingleEntityValue. 

an AggregateValue, representing a value of an EXPRESS BAG data type: a collection of instances of the member-type of the BAG, in which a given instance can appear more than once. 

Represents the relationship between a BAGValue and one value of the base data type (the "member" value). 

an AggregateValue, representing a value of an EXPRESS BAG data type: a collection of instances of the member-type of the BAG, in which a given instance can appear more than once. 

a SimpleValue, a value of the EXPRESS data type BOOLEAN: TRUE, FALSE 

represents a data item, an Instance that is an item of information that has an explicit data representation conveying its meaning. 

a TaggedInstance that represents an EXPRESS entity instance -- an instance of an entity data type, a view of an object that incorporates those properties and relationships that are significant to some particular purpose(s). 

A PartialEntityValue that completely describes an Instance of some EntityType(s) 

a ConcreteValue representing a named value of an EnumerationType. 

An AggregateValue representing the output of an AggregateInitializer. 

represents any real or conceptual object, information unit or data item. 

a SimpleValue, a value of the EXPRESS data type INTEGER: any mathematical integer value. 

an AggregateValue, representing a value of an EXPRESS LIST data type: a sequence of instances of the member-type of the LIST. 

represents one position in a ListValue and the instance of the member-type in that position. 

a SimpleValue, a value of the EXPRESS data type LOGICAL: TRUE, UNKNOWN, FALSE. 

A (complex) EntityInstance that is a valid instance of more than one EntityType and whose state includes more SingleEntityValues than are declared for, or inherited by, any named EntityType defined in the governing Schema. 

a SimpleValue, a value of the EXPRESS data type NUMBER: any numeric value with its mathematical interpretation. 

an Instance that is a collection of Attributes (of SingleEntityTypes) with associated values. 

a SimpleValue, a value of the EXPRESS data type REAL: supposedly a mathematical "real" value, but properly a computational fixed or floating-point value. 

an AggregateValue representing a value of a SET data type. 

Represents the relationship between a GenericAggregate and an Instance that appears in it. 

a ConcreteValue that consists of a single atomic information unit of a data type defined in the EXPRESS language itself. 

A collection of values for the explicit Attributes of exactly one SingleEntityType. 

An EntityInstance that is completely characterized by a single EntityType (and all its supertypes) that is declared in the governing Schema 

a TaggedInstance that is a value of a SpecializedType; every SpecializedInstance is represented by some ConcreteValue. 

a SimpleValue, a value of the EXPRESS data type STRING: a sequence of character codes from the ISO 10646-1 Basic Multilanguage Plane. 

an abstract classifier, a subtype of Instance that represents those Instances that are instances of a DataType that has an identifier (a Tag) and therefore may instantiate a SelectType.