3 . Using the answer to exercise 3 , remove all transitive dependencies , and draw the new dependency diagrams . For each new or revised table , specify its normal form .
Figure 3 – Solution 3
Discussion : The transitive relationship has been removed by creating the Publishers table , in which PubName is fully dependent upon PubCode . Pubcode also persists as a dependent attribute and Foreign Key in Books . All tables are now in 3NF , and have been given meaningful names reflecting the entities they represent . LINEITEMS represents the collection of line items for all invoices . Invoices represents the collection of Invoices for all customer orders . Books makes up the list of all books available for sale ( whether they have ever been ordered or not ). Each book has a publisher , and the publisher code and Name reside in the Publishers table .
4 . Draw the ERD for exercise 3 , using Crow ‘ s Foot notation . End of Sample Exercise . Student Exercise
The student exercise for this lab is similar to the sample exercise presented above .
Consider the following spreadsheet containing information about customers , their shipping and billing addresses , and the countries corresponding to each of those addresses . A customer may be associated with zero to many addresses . A customer may have 0 or 1 default billing address . A customer may have 0 or 1 default shipping address . Each address may be associated with 0 or 1 countries , while each country may be associated with 0 to many addresses .