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A literal null specifies the lack of a value.
Description
A literal null is used to represent null (i.e., the absence of a value).
Generalizations
•
“LiteralSpecification? on page 61
Attributes
No additional attributes
Associations
No additional associations
Constraints
No additional constraints
Additional Operations
[1] The query isComputable() is redefined to be true.
LiteralNull::isComputable(): Boolean;isComputable = true
[2] The query isNull() returns true.
LiteralNull::isNull() : Boolean;isNull = true
Semantics
LiteralNull is intended to be used to explicitly model the lack of a value.
Notation
Notation for LiteralNull varies depending on where it is used. It often appears as the word ‘null.’ Other notations are described
for specific uses.