The subjects of the two tables orders and merchandise have a many-to-many relationship.
ERDLab This affords a trouble. To apprehend the trouble, consider what might occur if you attempted to create the relationship between the two tables through adding the Product ID subject to the Orders table. To have multiple product consistent with order, you need a couple of document inside the Orders desk in line with order. You could be repeating order facts for every row that relates to a unmarried order — resulting in an inefficient design that could result in faulty records. You run into the identical hassle in case you positioned the Order ID subject within the Products desk — you would have a couple of document in the Products table for each product. How do you resolve this problem?