Version 20090528 - NHS LRA Terminology Binding Constraint Representation

Based on - Version20081130 - MRCM Addendum of SNOMED Interchange Format- Copyright IHTSDO

Top-level element that represents a complete referencable expression constraint on SNOMED CT expression.

The userRefset element is included to allow the Refsets used in the expression to be included in the file. This is optional since the Refsets may be shared using different mechanism (i.e. separate distribution files or from a shared repository).

Represents a complete and referencable constraint on a SNOMED CT expression.

The ExpressionConstraint can be identified using either a UUID or an SCTID and can be assigned a status and effectiveTime in line with the general characteristics of a SNOMED CT component.

A node in an ExpressionConstraint that specifies a constraint on a value within an expression. A value may be a single conceptId or a valid post-coordinated expression, including post-coordiated refinements.

A node in an ExpressionConstraint that specifies the permitted or prohibited values for a concept at the corresponding location in an expression.


The values are specified in one of a number of ways indicated by the 'rule' attribute. The supported rules allow individual conceptId values, subtype descents and members of a Refsets to be used to specify the values.
If the 'exclude' attribute is true this indicates that the specified values are prohibited rather than required.

Two or more ConceptConstraints (and/or nested ConceptConstraintSets) that are tested as a set. This is used to represent permitted (or prohibited) using a lists of identifiers or multiple rules.

The result of applying an ConceptConstraintSet depends on SetOperator and the constraints in the set.

SetOperation 'AND': all constraints in the set must be true.

SetOperator='OR': at least one constraint in the set must be true.

An operator that determines how a set constraints is tested.

A node in an ExpressionConstraint that specifies a permitted or required collection of refinements related to a particular node in the tested expression.

In most cases RefinementConstraints directly specifies the attributes and RelationshipGroups to be applied to the expression.

Constraints that permit alternative attributes (e.g. 'direct morphology' or 'procedure site direct') are represented using a RefineItemConstraintSet in which the alternative AttributeConstraints are joined by the 'OR' operator.

Where necessary more complex constraints are represented by nesting RefineItemConstraintSets to specify a permitted combinations and alternatives.

Two or more AttributeConstraints, GroupConstraints or (and/or nested RefineConstraintChoiceSets) that are tested as a set.

The result of applying an RefinementConstraintSets depends on SetOperator and the constraints in the set.

SetOperation 'AND': all constraints in the set must be true.

SetOperator='OR': at least one constraint in the set must be true.

A node in an ExpressionConstraint that specifies a permitted, required or prohibited attribute refinement.

Each refinement consists of a conceptId for an attribute followed by a value represented as a conceptId or as a post-coordinated expression.

The attributes minOccurs and maxOccurs indicate the number of attributes in the tested refinement that are required or permitted to conform to this constraint.

A node in an ExpressionConstraint that specifies a permitted, required or prohibited RelationshipGroup that forms part of a refinement. Each GroupConstraint specifies one or more AttributeConstraints (or AttributeConstraints sets) are tested to determine whether a RelationshipGroup conforms to the constraint.

The attributes minOccurs and maxOccurs indicate the number of RelationshipGroups in the tested refinement that are required or permitted to conform to this constraint.

Two or more AttributeConstraints (and/or nested AttributeConstraintSets) that are tested as a set.

The result of applying an AttributeConstraintSet depends on SetOperator and the AttributeConstraints in the set.

SetOperation 'AND': all constraints in the set must be true.

SetOperator='OR': at least one constraint in the set must be true.

Two or more ValueConstraints (and/or nested ValueConstraintSets) that are tested as a set.

The result of applying an ValueConstraintSet depends on SetOperator and the constraints in the set.

SetOperation 'AND': all constraints in the set must be true.

SetOperator='OR': at least one constraint in the set must be true.

If the exclude value is 'true' the interpretation of the concept is inverted. Thus to pass the constraint the concept must not be in the set of concepts specified.

The value 0 indicates that it is not necessary for any attributes in the refinement to match this constraint.

Values 1 and above indicate that at least the specified number of attributes in the refinement must match the constraint.

The default value 1 applies if no value is specified.

The value 0 indicates that it is prohibited for any attributes in the refinement to match this constraint.

Values 1 and above indicate that up to the specified number of attributes in the refinement may match the constraint.

The value * (unbounded) indicates that there is no upper limit to the number of matches permitted.

The default value 1 applies if no value is specified.

‘true’ – Attributes in groups contained in the same refinement also match this ungrouped AttributeConstraint. ‘false’ – Attributes in groups do not match this ungrouped AttributeConstraint.

Indicates whether, all permitted post-coordinated refinements of the value are specified by subsidiary constraint nodes (closed) or the subsidiary constraint nodes add restrictions to inherited constraints (open). In the 'open' view any refinements permitted by the concept model (and any inherited expression constraints) are permitted unless explicitly constrained. In the 'closed' mode view a refinement that is not mentioned is not permitted.

The value 0 indicates that it is not necessary for any RelationshipGroups to match this constraint.

Values 1 and above indicate that at least the specified number of RelationshipGroups in the refinement must match the constraint.

The default value 1 applies if no value is specified.

The value 0 indicates that it is prohibited for any RelationshipGroups in to match this constraint.

Values 1 and above indicate that up to the specified number of RelationshipGroups in the refinement may match the constraint.

The value * (unbounded) indicates that there is no upper limit to the number of matches permitted.

The default value 1 applies if no value is specified.

Indicates whether, all permitted post-coordinated refinements of the value are specified by subsidiary constraint nodes (closed) or the subsidiary constraint nodes add restrictions to inherited constraints (open). In the 'open' view any refinements permitted by the concept model (and any inherited expression constraints) are permitted unless explicitly constrained. In the 'closed' mode view a refinement that is not mentioned is not permitted.

Default type of constraint testing.

Note the referencing artifact can apply a different type of test. This attribute allows the constraint author to express its anticipated use.

Indicates whether the constraint incorporates derived constraints or assumes that the constraint is applied in addition to other constraints.

Allows a constraint to be given a display name

This name is intended to be used in search of picking list in tools that manipulate ExpressionConstraints. It should not be regarded as meaningful in terms of the processable semantics applied to information model artifacts.