IST 318 – DB Administration Intro to Relational Model, Normalization, and SQL

RDB Terminologies

RDBMS

RDBMS Functions

System Dev. Life Cycle (SDLC)

SDLC Illustration

E and R DB design should focus on organization (Management of Data), not limited to the Data (or numbers) What kinds of data are needed?  entities Real world people, objects, processes, concepts Turn into tables How are these kinds of data are related?  relationships Turn into constraints (and sometimes tables)

Cardinality One important type of relationship Binary relationship The most commonly considered constraint on a binary relationships is cardinality, or number of instances that may appear through this relationship One to one One to many Many to many

ER Diagram Notice the notations for Entities Relationships Cardinality constraints

Normalization – Why it’s needed? Notice the redundancy in the dataset (modeled with a single entity/table)? Problems (or anomalies) that can be induced Insertion, deletion, and update anomalies Normalization (or splitting into multiple tables) is the solution

Normalization – How to Do It? Split a “wide” table into a number of “narrow” ones that are in the third normal form (3NF) 1NF: data in every field is atomic, and the record has a (primary) key 2NF: all fields depend on the whole key 3NF: every field depends on the key directly, not through another (set of) field(s)

Sample Tables in 2/3NFs

ERD for The Sample Bookstore DB