business-rule-patterns

Business Rule Best Practices for ServiceNow

Business Rules are server-side scripts that execute when records are displayed, inserted, updated, or deleted.

When to Use Each Type

Available Objects

// In Business Rules, these are always available:
current // The record being operated on
previous // The record BEFORE changes (update/delete only)
gs // GlideSystem utilities

Before Business Rules

Use for validation and field manipulation:

// Prevent update if condition not met
;(function executeRule(current, previous) {
  if (current.state == 7 && previous.state != 6) {
    current.setAbortAction(true)
    gs.addErrorMessage("Must resolve before closing")
  }
})(current, previous)

// Auto-populate fields
;(function executeRule(current, previous) {
  if (current.isNewRecord()) {
    current.setValue("caller_id", gs.getUserID())
    current.setValue("opened_by", gs.getUserID())
  }
})(current, previous)

Never do in Before rules:

• Call current.update() (causes recursion!)
• Query other tables (keep it fast)
• External API calls

After Business Rules

Use for related record operations:

// Create child record when priority is P1
;(function executeRule(current, previous) {
  if (current.priority.changesTo(1)) {
    var task = new GlideRecord("task")
    task.initialize()
    task.setValue("short_description", "P1 Follow-up: " + current.number)
    task.setValue("parent", current.sys_id)
    task.insert()
  }
})(current, previous)