How To Fix W8198 - Value of type & is used for defining date (type &)

SAP Error Message - Details

• Message type: E = Error

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

• Message number: 198

• Message text: Value of type & is used for defining date (type &)

What causes this issue?

You are trying to assign an element of data type &v1& to an element of
data type &v2&.

System Response

In cases concerning assignments, a conversion is executed at runtime
involving &v1& in &v2&, under the following rules:
N -> D,,First the conversion N -> C takes place and then C -> D.
N -> C,,The numerical field is treated like a text field,
,,,,,,leading zeros are retained.
C -> D,, the text field should contain an 8-digit date in the form
,,,,,,YYYYMMDD.

How to fix this error?

You should ensure that only data type &V2& can be included when
calculating difference days. The necessary type conversions (MOVE) are
executed internally automatically before the arithmetic operation. For
reasons of efficiency, however, only operands of the same numeric data
type should occur within one arithmetic expression, if possible (up to
the operands for STRLEN): in such cases, no conversion is required and
special internal optimization can be carried out.

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 W8198 - Value of type & is used for defining date (type &) ?

  Certainly! Here's a detailed explanation for the SAP error message:
  
  SAP Error Message:
  W8198: Value of type & is used for defining date (type &)
  
  Cause:
  This warning message occurs when a value of a certain data type is used to define or assign a date variable, but the data type of the value does not match the expected date type. In other words, the system detects that a value of one data type (e.g., character or numeric) is being assigned or compared to a variable that is defined as a date type (DATS).
  For example, if you try to assign a character string or a numeric value directly to a date field without proper conversion, this warning will be triggered.
  
  Explanation:
  
  The message placeholders & are replaced by the actual data types involved.
  The system expects a date type (DATS) but finds a different type (e.g., CHAR, NUMC, or I).
  This is a warning (not an error), so the program will still run, but it indicates a potential data type mismatch that could lead to incorrect results or runtime errors.
  
  
  Typical Scenario:
  DATA: lv_date TYPE DATS,
        lv_char TYPE CHAR10.
  
  lv_char = '20240427'.
  lv_date = lv_char.  " This triggers W8198 warning
  Here, lv_char is a character string, and lv_date is a date. Direct assignment without conversion causes the warning.
  
  Solution:
  
  Convert the value explicitly to the date type before assignment.
  Use appropriate conversion functions or statements such as CONV, MOVE, or WRITE TO with formatting.
  
  Example solution:
  DATA: lv_date TYPE DATS,
        lv_char TYPE CHAR10.
  
  lv_char = '20240427'.
  lv_date = CONV DATS( lv_char ).  " Explicit conversion to date type
  Or, if the value is numeric or character but represents a date in a known format, convert it properly:
  DATA: lv_date TYPE DATS,
        lv_char TYPE CHAR10.
  
  lv_char = '20240427'.
  WRITE lv_char TO lv_date DATE 'YYYYMMDD'.
  
  Related Information:
  
  Data types in SAP ABAP:
  
  DATS - Date type (8 characters, format YYYYMMDD)
  CHAR - Character string
  NUMC - Numeric text
  
  
  Always ensure that date fields are assigned values of type DATS or properly converted values.
  This warning helps prevent runtime errors due to invalid date formats or data type mismatches.
  Check SAP Note or documentation for your specific SAP version if the warning persists or causes issues.
  
  
  Summary:
  
  
  
  Aspect
  Description
  
  
  
  
  Cause
  Assigning or using a value of a non-date type to define or assign a date variable (DATS).
  
  
  Effect
  Warning message W8198 is raised indicating a data type mismatch.
  
  
  Solution
  Convert the value explicitly to the date type before assignment using CONV, WRITE TO, etc.
  
  
  Notes
  This is a warning, not an error, but should be fixed to avoid potential runtime issues.
  
  
  
  
  If you need help with a specific code snippet or scenario, feel free to provide it!