How To Fix USMD1060 - Data model &1, ent. type &2: Relationship of type "leading" inconsistent

SAP Error Message - Details

• Message type: E = Error

• Message class: USMD1 - Datenmodel

• Message number: 060

• Message text: Data model &1, ent. type &2: Relationship of type "leading" inconsistent

What causes this issue?

Entity types with <DS:DE.USMD_USAGE_TYPE>storage and use type</> <LS>4
</> must be used as to-entity types in one relationship with the
relationship type <LS>Leading</>. You can use the from-entity type to
process the attributes or assignment of additional entity types using
the relationship type <LS>Referencing</>.
There is either more than one relationship with <LS>Leading</> as the
relationship type, or none at all.

System Response

The data model cannot be saved or activated.

How to fix this error?

Make sure that there is exactly one relationship with the relationship
type <LS>Leading</>.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.