2 Use Cases

In some situations, some parts of a SNOMED CT expression, expression constraint or query are not known at the time of authoring. In these situations, the SNOMED CT Template Syntax may be used, in conjunction with the appropriate language syntax, to represent a template of a specific type. For example:

• Using the Template Syntax with SNOMED CT Compositional Grammar enables the representation of ‘Expression Templates’;
• Using the Template Syntax with the SNOMED CT Expression Constraint Language enables the representation of ‘Expression Constraint Templates’; and

• Using the Template Syntax with the SNOMED CT Query Language¹  enables the representation of ‘Query Templates’.

Expression templates, expression constraint templates and query templates serve slightly different purposes. The following sections describe the key use cases for each of these template types.