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Published byJulius Hopkins Modified over 9 years ago
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What Is Normalization In relational database design, the process of organizing data to minimize redundancy Usually involves dividing a database into two or more tables and defining relationships between the tables The objective is to isolate data so that additions, deletions, and modifications of a field can be made in just one table and then propagated through the rest of the database via the defined relationships.
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Terminologies Candidate Key One of several possible attributes or combinations of attributes which can be used to identify each record uniquely in a table E.g., Employees( empID, SSN, lastName, firstName, address, phone, email, hireDate) Cadidate Keys: empID, SSN, lastName-firstName- address, email. The actual candidate key that is chosen for use is the primary key.
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Terminologies Primary Key A field in a table whose value is unique and insures that each record in the table is unique. Foreign Key A field in a table containing values that are also found in some primary key field (in a different table)—is used to link one table with another
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Levels of Normalization First Normal Form (1NF) eliminates repeating groups by putting each value of a multi-valued attribute into a new row Second Normal Form (2NF) eliminates functional dependencies on a partial key by putting the fields in a separate table from those that are dependent on the whole key Third Normal Form (3NF) eliminates functional dependencies on non- key fields by putting them in a separate table. At this stage, all non-key fields are dependent on the key, whole key, and nothing but the key.
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Lectures--Normalization Logic Modeling I (6:05) (Introduction) Logic Modeling I Logic Modeling II (5:56) (Candidate Key) Logic Modeling II Logic Modeling III (6:47) (Normalization) Logic Modeling III Logic Modeling IV (6:20) (Example) Logic Modeling IV Logic Modeling V (3:54) (First Normal Form) Logic Modeling V Logic Modeling VI (9:09) (Second Normal Form) Logic Modeling VI Logic Modeling VII (6:04) (Third Normal Form) Logic Modeling VII Logic Modeling VIII (9:09) (Entity Relation Diagram) Logic Modeling VIII
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Lectures (More informal) What Is Database Normalization (2:51) What Is Database Normalization Understanding Normalization: Rule of One (2:53) Understanding Normalization: Rule of One SQL Normalization (5:08) SQL Normalization Normalization Demonstration (7:49) Normalization Demonstration Database Normalization (w/Excel) (22:00) Database Normalization (w/Excel)
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