How To Fix DMC_EXCEPTION002 - Lookup tables cannot be part of any foreign key relationship

SAP Error Message - Details

• Message type: E = Error

• Message class: DMC_EXCEPTION - Message class for exception texts

• Message number: 002

• Message text: Lookup tables cannot be part of any foreign key relationship

A lookup table contains records that are looked up from a field in
another table to fill in the value of that field. The table can be
referenced by rules and used by mapping operations, but does not
directly provide content for fields in the target system.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message DMC_EXCEPTION002 - Lookup tables cannot be part of any foreign key relationship ?

  The SAP error message DMC_EXCEPTION002 indicates that lookup tables cannot be part of any foreign key relationship in the context of SAP Data Management or SAP HANA. This error typically arises when you attempt to create a foreign key relationship involving a lookup table, which is not allowed due to the nature of lookup tables.
  Cause:
  
  Lookup Tables: Lookup tables are designed to provide reference data and are not intended to enforce referential integrity through foreign key constraints. They usually contain static data that is used for validation or categorization.
  Foreign Key Constraints: Foreign key relationships are meant to enforce data integrity between two tables, ensuring that a value in one table corresponds to a valid entry in another. Since lookup tables are not meant to be part of such relationships, attempting to create one results in this error.
  
  Solution:
  To resolve this error, you can take the following steps:
  
  
  Review Table Design: Ensure that the table you are trying to create a foreign key relationship with is not a lookup table. If it is, you will need to reconsider your database design.
  
  
  Remove Foreign Key Constraints: If you have mistakenly defined a foreign key relationship with a lookup table, you should remove that constraint. This can typically be done through the database management interface or SQL commands.
  
  
  Use Alternative Approaches: If you need to reference data from a lookup table, consider using joins in your queries instead of foreign key constraints. This allows you to still access the necessary data without enforcing a foreign key relationship.
  
  
  Check Documentation: Refer to the SAP documentation or guidelines for best practices regarding the use of lookup tables and foreign key relationships. This can provide additional insights into how to structure your data model effectively.
  
  
  Related Information:
  
  Lookup Tables: These are often used for storing static reference data, such as country codes, status codes, or other categorical data that does not change frequently.
  Foreign Key Relationships: These are used to maintain referential integrity between tables, ensuring that relationships between data are valid and consistent.
  SAP HANA: If you are using SAP HANA, be aware of its specific rules and limitations regarding table relationships and data modeling.
  
  By following these guidelines, you should be able to resolve the DMC_EXCEPTION002 error and design your database schema appropriately.