A SNOMED CT template is a SNOMED CT expression, expression constraint, or query that contains one or more slots. Each template slot either provides information as to how the template should be processed (i.e. an information slot), or serves as a placeholder for a specific value that may be completed at a subsequent time. Each replacement slot may have a replacement type (e.g. concept, expression, token, string, integer, decimal or boolean), a slot name, and a replacement constraint. Depending on the replacement type, the replacement constraint may either be an expression constraint, a value list constraint or a range constraint. Each information slot may have a cardinality and a slot name.
The SNOMED CT template syntax defines the syntax used for these slots, irrespective of the computable language in which they are embedded. Figure 4-1 below illustrates the abstract model of the SNOMED CT template syntax. Please note that no specific semantics should be attributed to each arrow in this diagram.
Figure 4-1: Abstract model of SNOMED CT Template Syntax