ist 318 – db administration intro to relational model, normalization, and sql

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 o One important type of relationship Binary relationshipo The most commonly considered constraint on a binary

relationships is cardinality, or number of instances that may appear through this relationshipo One to oneo One to manyo Many to many

ER DiagramNotice 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