Lecture Notes for Feb 8, 2010

Databases 1 Monday, February 8th A set of well-formed tables Well-Formed Tables: I swear that each non-key column is dependent upon the key, the whole key, and nothing but the key, so help me Codd (non-technical). Well-Formed Tables: Every determinant is a candidate key (technical). ALGORITHM (Revised): 1.Identify all candidate keys in the relation. (JUSTIFY) 2.Identify one functional dependency in the relation. (JUSTIFY) 3.Examine its determinant. If it is not a candidate key, then the table is not well-formed. a.Place columns of the functional dependency into new table. b.Make the prime key of the table the determinant of the F.D. c.Leave a copy of this determinant in the original table to serve as a F.K. BUT delete non-determinant columns from original table. d.Create a Referential Integrity constraint between the two tables. REPEAT 2-3.d UNTIL ALL TABLES ARE WELL-FORMED Write down the name of the table; ALLCAPS Column Names; CamelCase 1.Identify all candidate keys in the relation. (JUSTIFY) Keys(column) that are unique per entry. Identify all of them! 2.Identify one functional dependency in the relation. (JUSTIFY) A column that determines the data of other columns of that row. 3.Examine its determinant. If it is not a candidate key, then the table is not well-formed. a.Place columns of the functional dependency into new table. b.Make the prime key of the table the determinant of the F.D. c.Leave a copy of this determinant in the original table to serve as a F.K. BUT delete non-determinant columns from original table. d.Create a Referential Integrity constraint between the two tables.