MUFIX COMMUNITY

DBBeginners Approach

What is the Database ?Why Database ? Types of Database .Keys & Keys types .Normalization .Database Engines .Starting SQL .

Agenda

A kind of filing cabinet that include a group of related data .

What is the Database

Data : the values actually stored in the database .

Integrity .No Redundancy .Security .Apply Standards .

Why Database

Flat Database:- All entities data grouped in one table .

Types of Database

Relational Database :- Divide entities data into

tables .

The key Is an entrance to the data in the Database .

Keys

Primary key .Foreign key .Composite key .

Types of keys

Primary key

Unique value .

Must have value (not null) .

Foreign key

Allow Redundancy .

Must have value (not null) .

Must have the same values in the parent table

Composite key

Key that contains two or more field to identify records .

Normalization

Process of organizing and refining relations within database .

Normal forms: are theoretical rules against which a relation is tested .

1NF

Each cell have atomic value .

2NF

Functional dependency on the primary key .

3NF

No transitive dependency (terminate redundancy) .

Database engine

Microsoft Access .

Oracle .

MySQL .

Sybase .

Structured query language (SQL)Language used to access and modify in

Relational Database .

SELECT department_name FROM departments;

Data Manipulation Language (DML)Select .Insert .Update .Delete .

Select SELECT department_name FROM departments;

Insert

INSERT INTO departments(department_id, department_name, manager_id, location_id)VALUES (70, 'Public Relations', 100, 1700);

Update

UPDATE employeesSET department_id = 70WHERE employee_id = 113;

Delete

DELETE FROM copy_emp;

DELETE FROM departments WHERE department_name = 'Finance';

Get Help

Thank you

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