delete records in child table where parent is missing or parent is like

old_par%

erpnext/patches/june_2012/delete_old_parent_entries.py

@@ -0,0 +1,17 @@
+def execute():
+	"""delete entries of child table having parent like old_par%% or ''"""
+	import webnotes
+	res = webnotes.conn.sql("""\
+		select dt.name from `tabDocType` dt
+		where ifnull(dt.istable, 0)=1 and
+		exists (
+			select * from `tabDocField` df
+			where df.fieldtype='Table' and
+			df.options=dt.name
+		)""")
+	for r in res:
+		if r[0]:
+			webnotes.conn.sql("""\
+				delete from `tab%s`
+				where (ifnull(parent, '')='' or parent like "old_par%%") and
+				ifnull(parenttype, '')!=''""" % r[0])

erpnext/patches/patch_list.py

@@ -452,4 +452,9 @@ patch_list = [
 		'patch_file': 'alter_tabsessions',
 		'description': "alter tabsessions to change user column definition"
 	},
+	{
+		'patch_module': 'patches.june_2012',
+		'patch_file': 'delete_old_parent_entries',
+		'description': "delete entries of child table having parent like old_par%% or ''"
+	},
 ]