Add event in transaction base correction (#15631)

diff --git a/erpnext/utilities/transaction_base.py b/erpnext/utilities/transaction_base.py
index 6ca3d5b..4845e0b 100644
--- a/erpnext/utilities/transaction_base.py
+++ b/erpnext/utilities/transaction_base.py
@@ -37,11 +37,18 @@
 			self._add_calendar_event(opts)
 
 	def delete_events(self):
-		events = frappe.db.sql_list("""select name from `tabEvent`
-			where ref_type=%s and ref_name=%s""", (self.doctype, self.name))
-		if events:
-			frappe.db.sql("delete from `tabEvent` where name in ({0})"
-				.format(", ".join(['%s']*len(events))), tuple(events))
+		participations = frappe.get_all("Event Participants", filters={"reference_doctype": self.doctype, "reference_docname": self.name,
+			"parenttype": "Event"}, fields=["name", "parent"])
+
+		if participations:
+			for participation in participations:
+				total_participants = frappe.get_all("Event Participants", filters={"parenttype": "Event", "parent": participation.parent})
+
+				if len(total_participants) <= 1:
+					frappe.db.sql("delete from `tabEvent` where name='%s'" % participation.parent)
+
+				frappe.db.sql("delete from `tabEvent Participants` where name='%s'" % participation.name)
+
 
 	def _add_calendar_event(self, opts):
 		opts = frappe._dict(opts)
@@ -54,11 +61,15 @@
 				"description": opts.description,
 				"starts_on":  self.contact_date,
 				"ends_on": opts.ends_on,
-				"event_type": "Private",
-				"ref_type": self.doctype,
-				"ref_name": self.name
+				"event_type": "Private"
 			})
 
+			event.append('event_participants', {
+				"reference_doctype": self.doctype,
+				"reference_docname": self.name
+				}
+			)
+
 			event.insert(ignore_permissions=True)
 
 			if frappe.db.exists("User", self.contact_by):