Find concepts using ECL

One of Snow Owl's powerful features is the ability to list concepts matching a user-specified query expression using SNOMED International's Expression Constraint Language (ECL) syntax. If you would like to know more about the language itself, visit the documentation on the official site.

In this example, we list the direct descendants of the root concept using the ECL expression <!138875005 (via the ecl query parameter), and also limit the result set to a single item using the limit query parameter:

curl -u "test:test" 'http://localhost:8080/snowowl/snomedct/SNOMEDCT/concepts?ecl=%3C!138875005&limit=1&pretty'

As no query parameter in this request would make Snow Owl differentiate between "better" and "worse" results (eg. a search term to match), concepts in the response will be sorted by identifier.

The item returned is, indeed, one of the top-level concepts in SNOMED CT: 105590001 |Substance|

{
  "items": [ {
    "id": "105590001",
    "released": true,
    "active": true,
    "effectiveTime": "20020131",
    "moduleId": "900000000000207008",
    "iconId": "substance",
    "score": 0.0,
    "memberOf": [ "723560006", "733073007", "900000000000497000" ],
    "activeMemberOf": [ "723560006", "733073007", "900000000000497000" ],
    "definitionStatus": {
      "id": "900000000000074008"
    },
    "subclassDefinitionStatus": "NON_DISJOINT_SUBCLASSES",
    "ancestorIds": [ "-1" ],
    "parentIds": [ "138875005" ],
    "statedAncestorIds": [ "-1" ],
    "statedParentIds": [ "138875005" ],
    "definitionStatusId": "900000000000074008"
  } ],
  "searchAfter": "AoEpMTA1NTkwMDAx",
  "limit": 1,
  "total": 19
}

The number 19 in property total suggests that additional matches exist that were not included in the response this time.