• An item category( seafood, Meat, chicken Eggs) has many items one or more varieties as one to one (1,1) in minimum car

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An Item Category Seafood Meat Chicken Eggs Has Many Items One Or More Varieties As One To One 1 1 In Minimum Car 1 (54.16 KiB) Viewed 55 times

• An item category( seafood, Meat, chicken Eggs) has many items one or more varieties as one to one (1,1) in minimum cardinality and one to many (1,M) in maximum cardinality • A user as a customer may or may not place orders as one to zero(1,0) in minimum cardinality and zero or many (0,M) in maximum cardinality because the register user may view the items and even add to cart but change her mind and may not place order due to some reasons. • Each order can have one or more items but should contain at least one item as one to one (1,1) in minimum cardinality and one to many (1,M) in maximum cardinality since the Order and Items are related through the weak entity Order_Item. • The weak entity Order_Item has composite primary key( Order Number Item_ID) as partial keys since the weak entity inherits them from the corresponding strong entities Order and Item • Each order has one payment only as one to one (1,1) in minimum cardinality and one to one (1,1) in maximum cardinality since each order has one payment transaction only at single point of time. The Total Item_Amount is a derived attribute for each item ordered which is derived by calculating as below • Order_Amount is a derived attribute which is updated as the sum of Total_Item_Amount of all items ordered in single Order. Shipping Fee is a derived attribute based on the Order_Amount. Final Amount is a derived attribute updated on payment which is the sum of Order_Amount and Shipping Fee. ER diagram in Crow's foot Model Copy GL C www. MaxLa PK T FOR FO