# Logical Record Architecture for Health and Social Care
## Discharge Summary Release 0.02

Contents
The content of this release is not comprehensive and is not fully validated and must not be used in live system implementations.
# Reference Model Class: HXIT
An abstract type, intended only to be used by the data types that specialise it. The LRA constrains of HXIT to prohibit the use of the HL7 v3 control act attributes defined by the standard. The type is therefore used to provide validTimeLow and validTimeHigh attributes for specifying the period of validity of a data type instance subject to the requirements that: the instance SHALL be a member of a class specified by package lra::technical::participants (or any sub-package thereof); or the instance SHALL be a member of a specialisation of the collection data type lra::datatypes::COLL. The first requirement is a further constraint on the ISO 21090 specification to ensure that data type history does not conflict with specification of the temporal semantics of a care record components. ## Attributes
Name | Data type | Occurs | Description
--- | --- | --- | ---
validTimeLow | Timestamp | 0..1 | As specified by ISO 21090, the time that the given information became or will become valid. Note: This is not the time that any system first observed the value, but the time that the actual value became correct (i.e. when a patient changes their name). This attribute is further constrained within the LRA to be of type Timestamp.
validTimeHigh | Timestamp | 0..1 | As specified by ISO 21090, The time that the given information ceased or will cease to be correct. This attribute is further constrained within the LRA to be of type Timestamp.
## Constraints
Type | Name | Specification
--- | --- | ---
extension requires root | Invariant | inv: controlActExtension.oclIsDefined implies controlActRoot.oclIsDefined
no HL7 v3 control act attributes in LRA | LRA Invariant | inv: controlActRoot.oclIsUndefined and controlActExtension.oclIsUndefined
unnamed constraint | Invariant | def: noHistory : Boolean = validTimeLow.oclIsUndefined and validTimeHigh.oclIsUndefined and controlActRoot.oclIsUndefined and controlActExtension.oclIsUndefined