How To Fix E2180 - Constant foreign key selected (select only one alternative)

E2180 - Overview

• Message type: E = Error

• Message class: E2 - DE Data Dictionary

• Message number: 180

• Message text: Constant foreign key selected (select only one alternative)

What causes this issue?

You created a foreign key field and also marked the foreign key as a
constant foreign key with an entry in column <LS>Constant</>.
With constant foreign keys, a constant is assigned to a table field.
Only this constant is checked.

System Response

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

How to fix this error?

Remove the entries for the foreign key field in columns <ZH><ZK>For.key
table</></> and <ZH><ZK>Foreign key field</></> or cancel the entry for
the constant.

Error message extract from SAP system. Copyright SAP SE.

E2180 - Details

• The SAP error message E2180, "Constant foreign key selected (select only one alternative)," typically occurs in the context of database operations, particularly when dealing with foreign key relationships in ABAP programs or when defining database views. This error indicates that the system has detected a situation where a constant foreign key is being used, which is not allowed in certain contexts.
  
  Cause:
  The error is usually caused by one of the following scenarios:
  
  Multiple Foreign Key Alternatives: When defining a foreign key relationship, if multiple alternatives are provided, the system expects only one to be selected. If the definition includes constants or multiple options, it leads to this error.
  Incorrect Data Model: The data model may have been incorrectly defined, leading to ambiguity in foreign key relationships.
  Improper Use of Constants: Using constants in a way that conflicts with the expected foreign key behavior can trigger this error.
  
  
  Solution:
  To resolve the E2180 error, consider the following