How To Fix W8191 - Field or field value restrictions for "change" event only

SAP Error Message - Details

• Message type: E = Error

• Message class: W8 - Workflow: Expressions, data flow

• Message number: 191

• Message text: Field or field value restrictions for "change" event only

What causes this issue?

It is only worth defining field and field value restrictions if the
event is created when a "change" occurs.

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?

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message W8191 - Field or field value restrictions for "change" event only ?

  Certainly! Here's a detailed explanation for the SAP error message W8191: Field or field value restrictions for "change" event only:
  
  Error Message
  W8191: Field or field value restrictions for "change" event only
  
  Cause
  This warning message occurs when you try to apply field or field value restrictions in a context other than the "change" event in SAP. In SAP, certain field restrictions or validations are only allowed or meaningful during the change event of a screen or a transaction.
  
  The "change" event refers to the point in the processing where the user has made changes to the screen fields, and the system is validating or restricting input values.
  If you attempt to apply these restrictions during other events (like PBO - Process Before Output, PAI - Process After Input, or other custom events), SAP issues this warning because the restrictions are only valid or supported during the change event.
  
  
  When does this happen?
  
  When you define field or field value restrictions (e.g., using Screen Field Properties, Input Checks, or Value Restrictions) in the screen flow logic or in the module pool program.
  When you try to enforce these restrictions outside the change event (for example, in the PBO or PAI events).
  
  
  Solution
  
  
  Apply field or field value restrictions only in the "change" event.
  
  Make sure that your code or configuration that enforces these restrictions is placed inside the change event of the screen or transaction.
  
  
  Check your screen flow logic or module pool program to ensure that the restrictions are not being triggered in other events.
  
  
  If you are using Screen Painter or Transaction variants, verify that the restrictions are assigned correctly and only for the change event.
  
  
  If you are implementing custom validations, move the validation logic to the change event.
  
  
  
  Related Information
  
  
  SAP Screen Programming Events:
  
  PBO (Process Before Output): Used to prepare the screen before it is displayed.
  PAI (Process After Input): Used to process user input after the screen is processed.
  CHANGE event: Triggered when a field value is changed by the user; used for validations and restrictions.
  
  
  
  SAP Notes and Documentation:
  
  Check SAP Notes related to screen field restrictions and validation.
  Refer to SAP documentation on Screen Programming and Module Pool Programming for detailed event handling.
  
  
  
  Transaction Variants and Field Restrictions:
  
  When creating transaction variants (SHD0), field restrictions are often applied in the change event to ensure proper validation.
  
  
  
  
  Summary
  
  
  
  Aspect
  Description
  
  
  
  
  Cause
  Field or field value restrictions applied outside the "change" event.
  
  
  Effect
  Warning message W8191 is issued.
  
  
  Solution
  Apply restrictions only in the "change" event.
  
  
  Related Info
  Screen programming events, transaction variants, module pool programming.
  
  
  
  
  If you provide the context where this message appears (e.g., during screen programming, transaction variant creation, or custom module pool development), I can help you with more specific guidance.