Understanding the delete toolbar operation

Click Delete or Discard to delete the currently visible rule. The results of this operation depend on whether the rule is checked out to you (and so is deleted from your personal RuleSet). If this rule is in an unlocked RuleSet that does not require check out, clicking Deletedeletes the rule. If the rule is checked out and so is in a personal RuleSet, Discard adds a line to the history of the (surviving) rule. You are prompted to confirm the operation.

Restrictions

Several conditions prevent a delete operation from completing:

You cannot delete a rule that belongs to a locked RuleSet version. Instead, however, you can in most situations create a blocked rule or withdrawn rule in your application that masks — makes invisible to rule resolution — a rule no longer useful or wanted in your application.
By definition, you can't delete standard rules, as they are part of the Pega 7 product. Many can be overridden, but none can be deleted.
You can't delete any rule or data instance unless allowed by an Access of Role to Object rule associated with your access role, and also not disallowed by any Access Deny rules associated with your access role.
You cannot delete a rule where the Circumstance or Start Time fields all are blank if your system contains other rules with identical keys that are circumstance-qualified or time-qualified. Delete the qualified rules first, and then delete the unqualified rule.
You can't delete an Operator ID at a time that the operator has checked-out rules. Have the operator sign in, and delete or check in all rules in the personal RuleSet.
You can't delete a concrete class that contains instances.
You can't delete a class — concrete or abstract — when the system contains rules with that class name as the Applies To class. You are prompted with a list of the rules that you must delete before the class rule itself is deleted.
You can't delete a RuleSet version rule that identifies a non-empty collection of rules. Delete each of the rules in the version first.
You can't delete a RuleSet for which a RuleSet version exists. Delete each version first.

Notes

If you delete a rule or data instance by mistake, you can perform a Save As operation if the form is still visible. (Click the Save As button first; you cannot immediately perform a Save or Check In of the deleted object.) If it is too late to do the Save As operation, see How to recover (undelete) a deleted rule.

Deleting a rule does not delete the associated History-Rule instances; these support auditing and the Recover function. Over time, the database table that (pr4_history_rule in the default schema) saves History-Rule instances may contain many rows that no longer are useful. Your database administrator may purge older rows of this table.

When you delete an empty class derived from the Work-, Data-, or Assign- base class, the system deletes the associated History- classes if they are also empty.

definitions blocked rule, circumstance, time-qualified rule, withdrawn rule