Figure 4-43: 5NF transformations sometimes remove duplicates. (Web site optimization) Going
Figure 4-43: 5NF transformations sometimes remove duplicates. Going further with the table-creation commands and record-insertion commands for each of the three separate 5NF tables, note that all records added are exactly the same as for adding to the pre-5NF table, with any duplicate records removed. Create the PROJECT_EMPLOYEE table and add records: CREATE TABLE Project_Employee ( project VARCHAR2(32) NOT NULL, employee VARCHAR2(32) NOT NULL, PRIMARY KEY (project, employee) ); INSERT INTO Project_Employee VALUES( Analysis , Brad ); INSERT INTO Project_Employee VALUES( Analysis , Riffraff ); INSERT INTO Project_Employee VALUES( Analysis , Magenta ); INSERT INTO Project_Employee VALUES( DW , Janet ); INSERT INTO Project_Employee VALUES( DW , Brad ); INSERT INTO Project_Employee VALUES( DW , Columbia ); INSERT INTO Project_Employee VALUES( HTML , Columbia ); INSERT INTO Project_Employee VALUES( HTML , Riffraff ); COMMIT; PROJECTALL Analysis Analysis Analysis DW DW DW HTML HTML EMPLOYEE Brad Riffraff Magenta Janet Brad Columbia Columbia Riffraff PROJECTALL Analysis Analysis DW DW HTML MANAGER Joe Jim Larry Gemima Jackson MANAGERALL Gemima Jackson Jackson Jim Jim Joe Larry Larry EMPLOYEE Columbia Columbia Riffraff Magenta Riffraff Brad Brad Janet Some duplicate rows were removed 119 Understanding Normalization
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