Could you provide information about the Boyce-Codd normal form?
The Boyce-Codd normal form (abbreviated BCNF) is a "key heavy" derivation of the third normal form. The simplest way I can think to define it is if the key uniquely identifies a row, but the key includes more columns than are actually required to uniquely identify a row, then a table is in BCNF. For example:
CREATE TABLE t_employees1 ( employee_id INT IDENTITY , last_name VARCHAR(25) NOT NULL , first_name VARCHAR(25) NOT NULL CONSTRAINT XPKt_employees1 PRIMARY KEY (employee_id, last_name, first_name) -- other columns as needed ) This example of the t_employees1 table is in BCNF. To coax it into 3NF (third normal form), I would use: CREATE TABLE t_employees2 ( Employee_id INT IDENTITY CONSTRAINT XPKt_employees2 PRIMARY KEY (employee_id) , last_name VARCHAR(25) NOT NULL , first_name VARCHAR(25) NOT NULL -- other columns as needed )
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