Account Account Constraint Code

This module adds a control on accounting accounts. When a user tries to change the code of an account that already has at least one journal item (a line in an accounting entry), Odoo blocks the change and shows an error message.

• The rule applies to the account.account model and checks the account.move.line model.
• It is triggered automatically whenever the code field is modified.
• If any journal item is linked to the account, the modification is rejected with the message: "You cannot change the code of account which contains journal items."
• No new menus, screens, or reports are added; the change is only a validation constraint.

This helps keep the audit trail consistent by preventing account codes from being altered after they have been used in transactions.