---
title: fr-idm-link-firstid-constraint
description: OID
component: pingds
version: 8.1
page_id: pingds:schemaref:at-fr-idm-link-firstid-constraint
canonical_url: https://docs.pingidentity.com/pingds/8.1/schemaref/at-fr-idm-link-firstid-constraint.html
---

# fr-idm-link-firstid-constraint

|                             |                                                                                                                                                          |
| --------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------- |
| *OID*                       | 1.3.6.1.4.1.36733.2.3.1.81                                                                                                                               |
| *Names*                     | fr-idm-link-firstid-constraint                                                                                                                           |
| *Description*               | An attribute used to support a unique constraint on the set of fr-idm-link-type, fr-idm-link-qualifier, fr-idm-link-firstiduniqueid, fr-idm-link-firstid |
| *Syntax*                    | [DirectoryString](s-DirectoryString.html)                                                                                                                |
| *Equality matching rule*    | [caseIgnoreMatch](mr-caseIgnoreMatch.html)                                                                                                               |
| *Ordering matching rule*    | [caseIgnoreOrderingMatch](mr-caseIgnoreOrderingMatch.html)                                                                                               |
| *Substring matching rule*   | [caseIgnoreSubstringsMatch](mr-caseIgnoreSubstringsMatch.html)                                                                                           |
| *Single value*              | false: multiple values allowed                                                                                                                           |
| *User modification allowed* | true                                                                                                                                                     |
| *Usage*                     | userApplications                                                                                                                                         |
| *Interface stability*       | Internal use only. Do not remove or modify. Subject to change without notice.                                                                            |
| *Origin*                    | OpenIDM DSRepoService                                                                                                                                    |
| *Schema file*               | 60-repo-schema.ldif                                                                                                                                      |
| *Used by*                   | [fr-idm-link](oc-fr-idm-link.html)                                                                                                                       |