INFS1603 Lecture Notes - Lecture 5: Logical Data Model, Conceptual Schema, Functional Dependency

• School: UNSW, UNSW Sydney
• Department: Information Systems
• Course: INFS1603
• Professor: All

Document Summary

Normalization: normalization is a process for converting complex data structures (relations) into simpler, more stable data structures. It is a process that is accomplished in stages. Is a technique that is used to define (cid:862)goodness(cid:863) of a relation: results in data structures that have some desirable properties. Is a certain state of a relation: can be determined by applying rules regarding dependencies, uses a concept called functional dependency. Inference rules: logical conclusions: a -> b (e. g. postcode -> state) functional dependencies; Fds: f is a set of given fds, f+ is the set of all implied fds. F+ is called the closure of f: fmin is the minimal set of fds that is equivalent to f. this minimal set of fds has no redundancies. Normalization: process for converting a relation to a standard (normal) form, normalization is about being able to, decompose a relation/table into smaller components.