Introduction to RDBMS

1. Introduction to
databases
Ram Kedem

2. Copyright 2014 © Ram Kedem. All rights reserved. Not to be reproduced without written consent
Objectives
• Defining Database
• Why do we need Database ?
• RDBMS High Overview
• RDBMS Main Charachterisitcs

3. Copyright 2014 © Ram Kedem. All rights reserved. Not to be reproduced without written consent
Defining Database
• What is a Database
• The actual server on which our data resides
• A method we use in order to save all our data
• Flat File (text file)
• Hierarchical Method
• Using Tables
• And many more ..

4. Copyright 2014 © Ram Kedem. All rights reserved. Not to be reproduced without written consent
Defining Database (1)
Database as a storage
• A storage by which our data is being kept, also refered as the
machine that runs our database program.

5. Copyright 2014 © Ram Kedem. All rights reserved. Not to be reproduced without written consent
Defining Database (2)
Database as a method
• Formally, a "database" refers to a set of related data and the
way it is structured or organized, a method we use in order to
store our data.
• Unstructured data (for example flat file)

6. Copyright 2014 © Ram Kedem. All rights reserved. Not to be reproduced without written consent
• A method we use in order to store our data
• Hierarchical data
Defining Database (2)
Database as a method

7. Copyright 2014 © Ram Kedem. All rights reserved. Not to be reproduced without written consent
• A method we use in order to store our data
• Structured data – using tables
• SQL language was developed in order to allow us retrieve data
from these structures (tables)
• This method is also refered as RDBMS – the Relational Database
Management System
Defining Database (2)
Database as a method

8. Copyright 2014 © Ram Kedem. All rights reserved. Not to be reproduced without written consent
Database Benefits
• Aside from storing our data and providing us a method to
keep it, databases have many more benefits :
• Efficient reads
• Efficient writes
• Enhanced security
• Recoverability
• And many more ..

9. Copyright 2014 © Ram Kedem. All rights reserved. Not to be reproduced without written consent
RDBMS High Overview
• Relational Database management system
• Table structures
Employee id First Name Last Name Department Id
100 Steven Spielberg 50
101 Quentin Tarantino 60
Department Name
Sales
IT
Department Id Department Name
50 Sales
60 IT
Employees Table
Departments Table

10. Copyright 2014 © Ram Kedem. All rights reserved. Not to be reproduced without written consent
RDBMS High Overview
• Relational Database management system
• Table structures
Employee id First Name Last Name Department Id
100 Steven Spielberg 50
101 Quentin Tarantino 60
Department Id Department Name
50 Sales
60 IT
Employees Table
Departments Table

11. Copyright 2014 © Ram Kedem. All rights reserved. Not to be reproduced without written consent
RDBMS Main Concepts
• Relational Structure – each table can be related to another
based on common column.
• Normalization - the process of organizing the attributes and
tables of a relational database to minimize data redundancy.
Basicaly each column should appear only once (normalized
state).
• Constraints – rules we can enforce on specific column.

12. Copyright 2014 © Ram Kedem. All rights reserved. Not to be reproduced without written consent
Essential Points
• The term Database can refer to the actual machine on which
we are saving the data. It may also refer the method we use to
store the data.
• Other than just keeping our data, databases provide many
benefits (efficient reads / writes, enchanced security, etc.)
• In RDBMS our data is stored in tables, each table can be
related to another. In most cases data should be normalized.
We can also use constraints to better enforce our data
integritiy.