Expression Constraint Language

Search

SNOMED CT Document Library

    Loading...

Versions Compared

Old Version 2

changes.mady.by.user Linda Bird

Saved on

compared with

New Version Current

changes.mady.by.user Kai Kewley

Saved on

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

...

This section provides a quick reference to the key syntax features of the Expression Constraint Language.

Syntax Overview

The following table summarises the key symbols used in the Expression Constraint Language's brief syntax, with the ECL version in which each symbol was introduced. For more information about the version history of ECL, please refer to the 'History' section in 1. Introduction.

set identified by a specified reference set concept

Symbol

Name

VersionNotes
|Pipe1.0Used on either side of a concept's term for human readability
*Any1.0Retrieves all concepts in the substrate
^Member of1.0Retrieves the referencedComponentId of all (active) members of a reference set (or set of reference sets)
^ [ A, B]Member of (with field selection)2.0Retrieves the values of fields A and B of all (active) members of a reference set (or set of reference sets) that match the included Member filters (if applicable)

<

Descendant of

1.0Retrieves all descendants (subtypes) of the specified concept excluding the concept itself

<<

Descendant or self of

1.0Retrieves all descendants (subtypes) of the specified concept including the concept itself

<!

Child of

1.1Retrieves all children (immediate subtypes) of the specified concept excluding the concept itself

<<!

Child or self of

1.4Retrieves all children (immediate subtypes) of the specified concept including the concept itself
>Ancestor of1.0Retrieves all ancestors (supertypes) of the specified concept excluding the concept itself

>>

Ancestor or self of

1.0Retrieves all ancestors (supertypes) of the specified concept including the concept itself

>!

Parent of

1.1Retrieves all parents (immediate supertypes) of the specified concept excluding the concept itself

>>!

Parent or self of

1.4Retrieves all parents (immediate supertypes) of the specified concept including the concept itself

!!>

Top of set

2.2Filters the results set, by matching only on concepts that have no ancestors within the set

!!<

Bottom of set

2.2Filters the results set, by matching only on concepts that have no descendants within the set

A#B

Alternate identifier

2.2Retrieves a single concept based on an alternate identifier, where A is the identifier scheme alias and B is the identifier code

AND

Conjunction

1.0Retrieves the intersection of the results of each sub-expressions

OR

Disjunction

1.0Retrieves the union of the results of each sub-expressions

MINUS

Exclusion

1.0Retrieves the members of the first expression and excludes the members returned by the second expression
:Refinement1.0Used before one or more attribute-value pairs to refine the set of concepts retrieved

[1..3]

Cardinality

1.0Used to indicate the minimum and maximum number of occurrences of attributes or relationship groups

R

Reverse flag

1.0Retrieves the set of attribute values (i.e. destination concepts) of a specified attribute for a specified set of concepts

.

Dot notation

1.2Retrieves the set of attribute values (i.e. destination concepts) of a specified attribute for a specified set of concepts
/*  */Comment1.1Allows comments to be added within the text of an expression constraint
{{  }}Description filter1.5Filters the result set, by matching only on concepts which have a description with a matching term, language, type, dialect and/or acceptability
{{ D }}Description filter1.6Filters the result set, by matching only on concepts which have a description with a matching term, language, type, dialect and/or acceptability
{{ C }}Concept filter1.6Filters the result set based on the definition status, module, effectiveTime and active status of each concept
{{ M }}Member filter2.0Filters the result set based on the value of specific fields in a reference set.
{{+ HISTORY}}History supplement2.0Supplements the results with relevant inactive concepts



Examples

The following table provides some examples of each of the key syntax features of the Expression Constraint Language.

...