To create the masking rule, assign the text matcher to identify SELECT lists that contain the Social Security column. If the SELECT list matches the security rule criteria, the Rule Engine applies the mask action to the SELECT list. The mask action hides all the digits of the Social Security number. Enable the keep matcher result option to store the matched result. Then, apply the Stop if Applied processing action. If the Rule Engine applies the action, the Rule Engine does not continue to process the SQL statement through the rule tree and forwards the rewritten request to the database. Otherwise, the Rule Engine processes the SQL statement through the next rule.