Logical Model

A SNOMED CT Compositional Grammar expression begins with an optional definition status, contains one or more focus concepts (represented by a concept identifier) and optionally has a refinement. Each refinement may contain grouped or ungrouped attributes (or both). An consists of the attribute name (represented by a concept identifier) together with the value of the attribute. The attribute value is either an expression or a concrete value (i.e. string, integer, decimal or boolean). Figure 2 below illustrates the overall structure of a compositional grammar expression using an abstract representation. Please note that no specific semantics should be attributed to each arrow in this abstract diagram.

Figure 2: Abstract model of a compositional grammar expression

Figure 3 below shows an example of an expression with the main components marked. These components will be explained further in the subsequent sections of this document.

Figure 3: The main parts of an example expression

Details

Figure 4 below provides a more formal representation of the logical model of SNOMED CT Compositional Grammar using a UML class diagram.

Figure 4: Logical Model of SNOMED CT Compositional Grammar

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