Many to Many relationship in Dimension Modelling - Part 3 (Fundamental Flaw, Weighing factor)
As discussed in previous post, the idea of attaching one product to many product group is fundamentally flawed. In previous example, we have seen that every time there is jump in Umbrella sales, they will be jump in Fashion sales and Seasonal sales. So, this is clearly not going help the trend analysis or intelligent decision making. Also, the schema proposed in previous example has an upper limit on the number of groups a product can belong to. If the business is happy with above limitations, you don't need to read further. However, business also agrees that it is a flaw and they would like to see what options are available - we can a step further. Depending on the nature of the business, we will assign a weighing factor to each product group for each item. This weighing factor (now on referred to as WF) will be less than 1 for each entry, such that the sum of WF for a product equals ONE . In our example, Umbrella is more of a seasonal product. It is also a fashion (because there...