Added some comments

aql/convertQuery.go

@@ -15,29 +15,29 @@ ConvertQuery converts an IncomingQueryJSON object into AQL
 func (s *Service) ConvertQuery(JSONQuery *entity.IncomingQueryJSON) (*string, error) {
 
 	// Check to make sure all indexes exist
-	// How many entities are there
-	numEntities := len(JSONQuery.Entities) - 1
-	// How many relations there are
-	numRelations := len(JSONQuery.Relations) - 1
+	// The largest possible id for an entity
+	largestEntityId := len(JSONQuery.Entities) - 1
+	// The largest possible id for a relation
+	largestRelationId := len(JSONQuery.Relations) - 1
 
 	// Make sure no entity should be returned that is outside the range of that list
 	for _, e := range JSONQuery.Return.Entities {
 		// If this entity references an entity that is outside the range
-		if e > numEntities || e < 0 {
+		if e > largestEntityId || e < 0 {
 			return nil, errors.New("non-existing entity referenced in return")
 		}
 	}
 
 	// Make sure that no relation mentions a non-existing entity
 	for _, r := range JSONQuery.Relations {
-		if r.EntityFrom > numEntities || r.EntityTo > numEntities {
+		if r.EntityFrom > largestEntityId || r.EntityTo > largestEntityId {
 			return nil, errors.New("non-exisiting entity referenced in relation")
 		}
 	}
 
 	// Make sure no non-existing relation is tried to be returned
 	for _, r := range JSONQuery.Return.Relations {
-		if r > numRelations || r < 0 {
+		if r > largestRelationId || r < 0 {
 			return nil, errors.New("non-existing relation referenced in return")
 		}
 	}