statement "ALTER TABLE TABLE_NAME ADD FIELD_A BOOLEAN" leads in wrong error message "validation error for column TABLE_NAME.FIELD_B" on update statements

[DanielBauten]

Initial situation

• Server version: WI-V-6.3.3.3.1683 Firebird 5.0 (Firebird 5.0.3 @ Windows 11)
• Client library: 5.0.3.1683

Problem

• see attached database (password protected 7z-file; password via PM)
• execute statement ALTER TABLE ED_PARAMETER ADD INDEXENABLED BOOLEAN
• executing the statement update ED_PARAMETER set INDEXENABLED = true leads in wrong error message

  The insert failed because a column definition includes validation constraints.
  validation error for column "ED_PARAMETER"."MEMO", value "*** null ***".
  ------------------------------------------------------------------------------
  SQLCODE: -625
  SQLSTATE: 23000
  GDSCODE: 335544347
  

• but select ID, INDEXENABLED, MEMO from ed_parameter where (MEMO is NULL) is empty
• remark: even update ED_PARAMETER set ID = ID leads in above wrong error message

Workaround 1

• backup and restore database

Workaround 2

• the statement update ED_PARAMETER set MEMO = '' where (MEMO = '') or (MEMO is NULL) fixes the problem
• i.e. update ED_PARAMETER set INDEXENABLED = true is working as expected (without wrong error message)

Firebird-Bug 'validation error for column'.7z.zip