siluo
Registered: June 2010
Posts: 9
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“[ link ] Each Order contains one or more Products.” (At least one because it doesn't make sense [ link ] to place an order for no products.)“Each Product is contained in zero or more Orders.” (Zero because we might not have sold any of this product yet.)Since the maximum multiplicity in each direction [ link ] is “many,” this is called a many-to-many association between Orders and Products.Each time an order is placed for a product, we need to know how many units of that product are being ordered [ link ] and what price we are actually selling the product for. (The sale price might vary from the list price by customer [ link ] discount, special sale, etc.) These attributes are a result of the association between the Order and the Product. We show them in an association class that is connected to the association by a dotted [ link ] line yjh.
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