How To Fix UAS012 - Not possible to change column "&1" of type "&2"

SAP Error Message - Details

• Message type: E = Error

• Message class: UAS -

• Message number: 012

• Message text: Not possible to change column "&1" of type "&2"

What causes this issue?

You changed the attributes 'key field', 'language-dependent text' or
'posting level' of column &v1& of type &v2&. This change is not possible
because the database tables concerned already contain data and an
automatic conversion of this data is not supported.

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?

To make the change, you must first delete the existing data for this
type.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message UAS012 - Not possible to change column "&1" of type "&2" ?

  The SAP error message UAS012, which states "Not possible to change column '&1' of type '&2'," typically occurs when there is an attempt to modify a database table column that is not allowed due to its data type or constraints. Here’s a breakdown of the cause, potential solutions, and related information:
  Cause:
  
  Data Type Restrictions: The column you are trying to change may have a data type that does not support the intended modification. For example, you cannot change a column from a numeric type to a character type directly.
  Constraints: The column may have constraints (like primary keys, foreign keys, or unique constraints) that prevent changes.
  Data Integrity: The existing data in the column may not comply with the new data type or constraints you are trying to apply.
  Database Locking: The table might be locked by another transaction, preventing changes.
  
  Solutions:
  
  Check Data Type Compatibility: Ensure that the new data type you are trying to apply is compatible with the existing data. If not, you may need to create a new column, migrate the data, and then drop the old column.
  Remove Constraints: If there are constraints on the column, you may need to temporarily remove them before making the change and then reapply them afterward.
  Data Migration: If the existing data does not fit the new data type, you may need to clean or transform the data before changing the column type.
  Use the Correct Transaction: Ensure that you are using the appropriate transaction or method to make the changes. For example, using SE11 for data dictionary changes.
  Check for Locks: Use transaction SM12 to check for any locks on the table and resolve them if necessary.
  
  Related Information:
  
  Transaction Codes: Familiarize yourself with relevant transaction codes such as SE11 (Data Dictionary), SE14 (Database Utility), and SE37 (Function Builder) for making changes.
  SAP Notes: Check SAP Notes for any specific issues related to the error message UAS012, as there may be patches or updates that address known issues.
  Documentation: Review SAP documentation regarding data types and constraints to understand the limitations and requirements for modifying database tables.
  
  If the issue persists after trying the above solutions, consider reaching out to your SAP Basis or development team for further assistance, as they may have more insights into the specific configuration and constraints of your SAP environment.