# 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: RTO
This is as is in ISO 21090 other than the specific constraint to prevent the use of CO as a data type for the numerator and denominator. ## Specializes ## QTY ## Attributes
Name | Data type | Occurs | Description
--- | --- | --- | ---
denominator | QTY | 0..1 | Must not be coded ordinal (CO)
numerator | QTY | 0..1 | Must not be coded ordinal (CO)
## Constraints
Type | Name | Specification
--- | --- | ---
no coded ordinal ratios in LRA | LRA Invariant | inv: (not numerator.oclIsTypeOf(CO)) and (not denominator.oclIsTypeOf(CO))
no uncertainty | Invariant | inv: uncertainty.isNull
no updateMode or History on RTO Attributes | Invariant | inv: noUpdateOrHistory(numerator) and noUpdateOrHistory(denominator)
numerator and denominator required | Invariant | inv: isNull xor (numerator.isNotNull and denominator.isNotNull)