Entity Relationship Diagram

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Assignment 1 Entity Relationship Diagram

PHILIP YUNFEI CHANG                 187542

  1. Information Requirements:
  • The new system shall:
  1. Manage details of its inventory;
  2. Manage relevant information of each employee;
  3. Manage relevant information of each supplier;
  4. Manage relevant information of each customer;
  5. Maintain record of each order placed;
  6. Maintain record of each delivery received;
  7. Maintain record of each prescription handled;
  8. Maintain record of each sale made;
  • The new system shall be able to handle the following tasks which the old system didn’t handle well:
  1. Monitor the quantity of items in stock and reduce the dependence of operations on stock-take;
  2. Maintain up-to-date prices of each item from multiple suppliers;
  3. Monitor the expiry dates of medications in stock and sell as many items as possible before they expire;
  4. Orders are made by authorized employees only and whoever placed an order can be traced back.
  5. Maintain control over access to inventory. (Whenever an item is picked from the inventory, relevant information is recorded)
  6. Prescription sales do not occur without valid prescriptions.
  7. Records of prescription to controlled substances are ready to be collected for inspection.
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  1. Assumptions:
  • Operational Assumptions:
  1. Though each item (An item is an instance of INVENTORY. It refers to all products of the same model/type rather than a single unit of product.) is identified by Item_ID, the entry interface still accepts both Item_ID and the Item_Name to refer to a particular item for the convenience of human workers. Whenever the name of an item is entered instead of its ID, an application automatically translates the name into its Item_ID according to a list of known names of each item. (This table wasn’t shown in the E-R Diagram to reduce the ...

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