In my project I have a table of customers, each customer has his own special price for each product, It's a small business and there are currently about 5 products. The manager says there might be more products in the future, but the business won't exceed 30 products. It's easier for me to not create special products table but to add columns to customer table (each new product - new column).
People advised me against it, but I didn't get an explantaion WHY still can't understand why in such case that product's prices has no relation (each customer has his own special price) adding rows to Products table is better then adding columns of products to Customers table? The only benefit I could think of is that customer that has only 5 products won't have to 'carry' 20 nullable products (saves space on server)?
any help would be greatly appreciated