UNS OpenHubDocumentation

Schema administration

Understand and create a relationship rule

A relationship rule describes how one object type can connect to another. Use this guide when inspecting an existing rule or creating one; neither action creates a connection between individual objects by itself.

Applies to
Schema · Relationship rule · View, Edit, and New
Guide version
1.0

Worked example

Example: material renumbering

Use this when one material identifier replaces another while both refer to the same material lineage.

Relationship key material-renumbering

Stable identifier used by evidence and integrations.

From / To object type material → material

Restricts this rule to material objects at both ends.

Relationship meaning renumbered_to

Machine-readable verb that states what the link means.

Direction Directed (From → To)

The previous material points to its replacement.

Allowed connections One to one

Each material has at most one replacement through this rule.

Status Draft

Keep it in draft while reviewing the meaning and evidence source.

Procedure

Follow the task in order

  1. 1
    Choose a stable keyUse lowercase words joined with hyphens. Changing a key later can break evidence and integrations that reference it.
  2. 2
    Set the From and To object typesSet both when the rule is only valid for particular types. Leave an endpoint blank only when any type is genuinely valid there.
  3. 3
    Describe the meaning and directionThe meaning is a machine-readable verb. Directed relationships always read from the From type to the To type.
  4. 4
    Limit the allowed connectionsSelect the cardinality that matches the business rule before making it active.
  5. 5
    Save as draft firstReview a new rule with the people who publish or interpret the relationship evidence, then set it active when it is ready to use.

Expected result

What you should have

A reusable schema rule. Manual links and approved relationship evidence can use this key to create individual ObjectId-to-ObjectId connections.

Boundaries

Important boundaries

  • A rule does not create or change existing object connections.
  • For a package-owned relationship, choose Edit package definition from Schema. The change remains a package candidate until it is reviewed and applied.
  • Use a new key for a changed meaning instead of silently repurposing an active rule.

This versioned public guide is maintained with the UNS OpenHub website and linked directly from the controller where the task applies.