ContributionsMost RecentMost LikesSolutionsis Reference proxy must be uniqueIs reference proxy must be unique , I've been a handled an app which has reference proxy field & not unique , Actually , The reference proxy for the grand child is the same as the parent means that :- A- In 1-m relation ship between (grandfather& parent) reference proxy field in unique in the grandfather table. That's correct B - The second 1-M relationship (parent & grand child ) reference proxy is the same field used in the previous relationship. ( Not unique & it used in the higher 1-M relationship) Here is the paradox I feel that is not correct at all ,Right ? See the below image to explain ------------------------------ Yasser Sabry ------------------------------ M-M relationship Dears, for M-M relationship It's only work if we make a third joined table, Right ? Making two 1-M relationship between the two tables is wrong ? correct ? By saying wrong I mean it will be logically incorrect , So If Someone handled an app to me with this procedure I need to create joined table instead of two 1-M relationship between the two tables right ? ------------------------------ Yasser Sabry ------------------------------