ICT 301 Lecture Notes - Lecture 6: Unique Key, Third Normal Form, Second Normal Form
21 Sep 2017
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Decomposition (database normalization) characteristics like insertion, update and deletion anomalies. Systematic approach of decomposing tables to eliminate data redundancy and undesirable: tables and properties of data, decompose based on properties, check on whether final set of tables satisfies no anomalies and no loss of information. 1nf (first normal form): relations contain comma values in its cell. Any row must not have a column in which more than one value is saved, like. A column must depend in its entirety to a whole primary key. Every non-prime attribute of a table must be only dependent on primary key. If ssn name it does not apply that name ssn. Therefore, ssn name is a one to many relationship. ssn must be unique but . Ssn is called the key for the functional dependency can have duplicates as long as for every unique ssn there is the same name.
