1249 9781449325572 2015-02-22 PHP & MySQL : The Missing Manual 1118 O ‘ Reilly Media , Incorporated 6 29.95
1249 9781890774790 2015-02-22 Murach ‘ s PHP and MySQL , 2nd Edition 1032 Murach , Mike & Associates , Inc 1 48.95
BookSales
1 . Using the BookSales table structure shown above , draw the dependency diagram , and show all dependencies , full , partial , and transitive .
Figure 1 -solution 1
Discussion : A composite primary key consisting of InvNum + ISBN13 can be constructed , ensuring that all rows are unique . All remaining attributes are shown to be dependent ( at least partially ) on this composite key , so the table is 1NF . Further analysis shows that InvDate is dependent on only part of the key ( InvNum ), and that unitPrice , PubCode , and BookTitle also depend on part of the key ( ISBN13 ). A transitive relationship is also revealed : PubName truly depends on PubCode , which in turn depends on ISBN13 .
2 . Using the answer to exercise 1 , remove all partial dependencies and draw the new dependency diagrams . For each new table created , specify its normal form ( 1NF , 2NF , 3NF ).
Figure 2- solution 2
Discussion : To achieve 2NF , we must remove partial dependencies . This is done by decomposing into three tables , and three dependency diagrams at this stage . Notice that the Transitive relationship has not yet been addressed .