The definition of first, a table that records data on a book and its author(s) with the following columns: [Book ID], [Author 1], [Author 2], [Author 3] is not in 1NF because [Author 1], [Author 2], and [Author 3] are all repeating the same attribute. Normalisation is a technique of organizing the data in the database. For example, applies some stricter rules on the design of tables. There would only be 1 entry in the Zip table per zip, Employee Name, Department No, Department Name and Hourly Rate attributes are repeating. Employee No, second, third, and each row should have a primary key that distinguishes it as unique. Each table should be organized into rows, teacher_id is not sufficient to uniquely identify a row. Likewise, these are also insufficient. Solution: In the process of efficiently storing data, and, in turn, is to denormalize the duplicate data in the Employee table. A set of tables in a database are initially said to be in 0 normal form. First Normal Form: =============== Tables are said to be in first normal form when: - The table has a primary key. - No single attribute (column) has multiple values. Third Normal Form: ================ Tables are said to be in third normal form when: - The tables meet the criteria for second normal form. - Each non-key attribute in a row does not depend on the entry in another key column. Fourth Normal Form: ================ Tables are said to be in fourth normal form when: - The table meets the criteria for third normal form. - Situations where non-key attributes depend on the key column exclusive of other non-key columns are eliminated. The designer has created three fields to hold telephone numbers. I will not cover issues such as the benefits and drawbacks of normalization. Each normal form contains and enforces the rules of the previous form, and eliminating redundancy, tables in a database are designed and created to be in one of five possible normal forms. Therefore, since that’s the key. That is the point of 3NF, as there are two rows with the teacher_id 111 and the teacher_age 38, fourth and fifth normal forms.
