...

	<< 404684003 |Clinical finding|:
		>> 24607500342752001 |CausativeDue agentto| = << 267038008 |Edema|

This expression constraint is represented in the long syntax as:

	descendantOrSelfOf 404684003 |Clinical finding|:
		ancestorOrSelfOf 42752001 246075003|CausativeDue agentto| = descendantOrSelfOf 267038008 |Edema|

...

The revised SNOMED CT Compositional Grammar allows attributes to be given concrete values (e.g. Strings, Integers, Decimal, Boolean). The SNOMED CT Expression Constraint Language supports the ability to compare these attribute values with a given concrete value.

When numeric concrete values (i.e. Integers and Decimals) are compared, a set of standard mathematical operators may be used. These mathematical operators are:

...

The following expression constraint is satisfied only by amoxicillin tablets, whose strength is oral medicinal products, which contain amoxicillin and have a presentation strength greater than or equal to 200 mg

.  

250 mg.

<763158003 |Medicinal product (product)|:
	411116001 |Has manufactured dose form (attribute)| = << 385268001 |Oral dose form (dose form)|,
	{	<< 127489000 |Has active ingredient (attribute)| = << 372687004 |Amoxicillin (substance)|,
 		1142135004 |Has presentation strength numerator value (attribute)| >= #250, 
		732945000 |Has presentation strength numerator unit (attribute)| = 258684004 |milligram (qualifier value)|}	

Please note that, as per SNOMED CT Compositional Grammar, integer and decimal values are preceded by a hash character (e.g. "#500"), while string values are surrounded by double quotes (e.g. "PANADOL").

To find those oral amoxicillin products that have a strength between 250 and 800 mg (inclusive), the following expression constraint may be used:

	< 27658006 |Amoxicillin<763158003 |Medicinal product (product)|:
		411116001 |Has manufactured dose form (attribute)| = << 428673006 |Tablet 385268001 |Oral dose form (dose form)|,
	{	<< 127489000 |Has active ingredient (attribute)| = << 372687004 |Amoxicillin (substance)|,
 		{ 1799999991001142135004 |Has basispresentation ofstrength strength|numerator =value (attribute)| 219999999102 |Amoxicillin only|:>= #250, 
			1899999991031142135004 |Has presentation strength magnitude numerator value (attribute)| ><= #200#800, 199999999101
		732945000 |Has presentation strength numerator unit (attribute)| = 258684004 |mg|)}

Please note that, as per SNOMED CT Compositional Grammar, integer and decimal values are preceded by a hash character (e.g. "#500"), while string values are surrounded by double quotes (e.g. "PANADOL").

milligram (qualifier value)|}	

Concrete values of type string and boolean may also be included in an expression constraint, and compared using an 'equal to' (i.e. "=") or 'not equal to' (i.e. "!=") operator. The following expression constraint is satisfied only by products with a product name equal to "PANADOL"

. To find those capsules that have a strength between 500 and 800 mg (inclusive), the following expression constraint may be used:

	< 373873005 |Pharmaceutical / biologic product	< 27658006 |Amoxicillin|:
		411116001 |Has dose form| = << 428673006 |Tablet|,
		{ 179999999100 |Has basis of strength| = ( 219999999102 |Amoxicillin only|:
			1899999991033460481009 |Has strengthproduct magnitudename| >= "PANADOL" #500, 
			189999999103 |Has strength magnitude| <= #800, 
			199999999101 |Has strength unit| = 258684004 |mg|)}         

Concrete values of type string may also be included in an expression constraint, and compared using an 'equal to' (i.e. "=") or 'not equal to' (i.e. "!=") operator. The following expression constraint is satisfied only by products with a trade name equal to "PANADOL"

that are in the national benefit scheme (of the given country)

.. 

	< 373873005 |Pharmaceutical / biologic product|:
		209999999104859999999102 |Has trade nameIs in national benefit scheme| = "PANADOL"                TRUE

Reverse Attributes

In most cases, an attribute refinement is satisfied by those concepts, which are the source concept of a defining relationship whose destination concept matches the attribute value. In some cases, however, it may be necessary to select the destination concept of a relationship and constrain the source concept to a given attribute value. To achieve this, an expression constraint indicates that an attribute is to be constrained in the reverse order using a 'reverse flag'

...

	descendantOf 91723000 |Anatomical structure|:
		reverseOf 363698007 |Finding site| = descendantOf 125605004 |Fracture of bone|

Anchor
DottedAttributes DottedAttributes

Dotted Attributes

An alternative way of representing 'reversed attributes' is by applying the dot notation to represented them as dotted attributes. Using this alternative notation, "

...

	< 125605004 |Fracture of bone|.363698007 |Finding site|

The next example below finds the set of substances, which are active ingredients of a 'TRIPHASIL tablet'an active ingredient in any product containing amoxicillin.

	< 105590001 |Substance|: 
		R << 127489000 |Has active ingredient| = < 24999999910127658006 |TRIPHASILProduct containing tabletamoxicillin|

This expression constraint is represented in the long syntax as:

	descendantOf 105590001 |Substance|: 
		reverseOfReverseOf descendantOrSelfOf 127489000 |Has active ingredient| = descendantOf 24999999910127658006 |TRIPHASILProduct containing tabletamoxicillin|

An equivalent way of representing this constraint, using the 'dot notation' is:

	< 105590001 |Substance| AND (249999999101 < 27658006 |TRIPHASILProduct containing tabletamoxicillin| . << 127489000 |Has active ingredient| )

or (using the

	249999999101< 27658006 |TRIPHASILProduct containing tabletamoxicillin| . << 127489000 |Has active ingredient|

...