Chapter 7 presents the following content: Informal design guidelines for relational databases, semantics of the relation attributes, redundant information in tuples and update anomalies, null values in tuples, introduction to normalization, first normal form, second normal form, third normal form, BCNF (boyce-codd normal form),. | Normalization for Relational Databases Informal Design Guidelines for Relational Databases Relational database design: The grouping of attributes to form "good" relation schemas Two levels of relation schemas: ◦ The logical "user view" level ◦ The storage "base relation" level Design is concerned mainly with base relations Criteria for "good" base relations: ◦ Discuss informal guidelines for good relational design ◦ Discuss formal concepts of functional dependencies and normal forms 1NF 2NF 3NF BCNF Semantics of the Relation Attributes Each tuple in a relation should represent one entity or relationship instance ◦ Only foreign keys should be used to refer to other entities ◦ Entity and relationship attributes should be kept apart as much as possible ◦ Design a schema that can be explained easily relation by relation. The semantics of attributes should be easy to .
