How To Fix AD284 - &-&: Foreign key cannot be specified in full

SAP Error Message - Details

• Message type: E = Error

• Message class: AD - Data Dictionary application messages

• Message number: 284

• Message text: &-&: Foreign key cannot be specified in full

What causes this issue?

It is not fully possible to define of the foreign key. When defining
the foreign key, a foreign key field must be assigned to each primary
key field of the check table or a field must explicitly be assigned a
constant or excluded from the check.
The assignment in the check field uses the common domains of the pair
of fields. The ABAP Dictionary data type and the length must be
consistent for all other pairs of fields.

System Response

The system automatically attempted to make a suggestion for this
assignment. However, the corresponding fields of the table to be
checked could not be assigned to all the primary key fields.

How to fix this error?

In order to activate a table with foreign keys, the assignment of check
fields and foreign key fields must be complete. The missing field
assignments must be maintained manually, whereby the fields to be
checked can come from a foreign table as well as from the table itself.
Constants can also be used for the missing field assignments or the
field can be removed explicitly from the assignment to the key fields
of the check table (generic foreign key). In this case the check is
only made against the remaining fields.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message AD284 - &-&: Foreign key cannot be specified in full ?

  The SAP error message AD284 typically indicates an issue related to foreign key constraints in the context of database table definitions. This error occurs when you attempt to define a foreign key relationship in a way that is not fully specified or is inconsistent with the existing database schema.
  Cause:
  
  Incomplete Foreign Key Definition: The foreign key relationship may not be fully defined, meaning that the referenced table or fields are not correctly specified.
  Data Type Mismatch: The data types of the foreign key fields in the referencing table and the primary key fields in the referenced table may not match.
  Non-Existent Table or Field: The table or field you are trying to reference in the foreign key does not exist or is misspelled.
  Multiple Keys: If you are trying to create a foreign key that references multiple fields, you need to ensure that all fields are correctly specified.
  
  Solution:
  
  Check Foreign Key Definition: Review the foreign key definition in the table where the error occurs. Ensure that all referenced fields and tables are correctly specified.
  Verify Data Types: Ensure that the data types of the foreign key fields match those of the primary key fields in the referenced table.
  Correct Table and Field Names: Double-check the names of the tables and fields to ensure they are spelled correctly and exist in the database.
  Use Full Specification: If you are defining a composite foreign key (a foreign key that consists of multiple columns), make sure to specify all columns in both the referencing and referenced tables.
  Check for Existing Constraints: Ensure that there are no existing constraints that conflict with the new foreign key definition.
  
  Related Information:
  
  Transaction Codes: You can use transaction codes like SE11 (Data Dictionary) to view and modify table definitions and foreign key relationships.
  Documentation: Refer to SAP documentation for detailed guidelines on defining foreign keys and constraints in the ABAP Dictionary.
  SAP Notes: Check SAP Notes for any known issues or updates related to this error message, as there may be specific patches or recommendations provided by SAP.
  
  If the issue persists after checking the above points, consider reaching out to your SAP Basis or ABAP development team for further assistance, as they may have more insights into the specific configuration of your SAP environment.