Check for the fields type in the sql_insert_generate() function

functions.py

@@ -117,6 +117,12 @@ def pil2buffer( img, format ):
     return buff
 
 def sql_insert_generate( table, fields, returning = None ):
+    if isinstance( fields, ( str ) ):
+        fields = [ fields ]
+    
+    if not isinstance( fields, ( list, tuple, ) ):
+        raise Exception( "list or tuple needed as fields" )
+    
     f = ",".join( fields )
     place_holder = ",".join( [ "%s" ] * len( fields ) )
     sql = "INSERT INTO {} ({}) VALUES ({})".format( table, f, place_holder )