Fundamentals of Database Systems

By Berhanu Abebe

Chapter 1 - Introduction• Computers • Purpose of computers• Database• Benefits of Database• Database Vs flat files• Users of a Database• DBMS• Purposes of DBMS

Introduction • Data • Information • Data processing

• What is data for someone may be an information to the other and vice versa.

Computers • An electronic machine that Accepts inputs Processes themStores the resultDisplays the output• The main task of a computer is to transform

data into information.• The computer can do this by storing the data in

a database and then by querying the database you can get an information out of data.

Database • Database – shared collection of logically related

data.Data that is organized and stored in

a computer and can be searched and retrieved by a computer program.

Benefits of Database• Data can be shared• Concurrent access of data• Reduced redundancy • Quality data can be maintained –

constraints, data type specifications• Security measures can be enforced • Speed will be enhanced ( for searching

data and …)• Centralized information control

Why not text files, Spreadsheets

• Data integrity• Redundancy• Outdated data• Data size• Retrieval • Searching• Filtering• Protecting data from unauthorized use• Protecting data from becoming corrupt

Database users• The people who interact with the database.1. End users – updating, inserting or modifying data

from the database naïve users – only access the database based on

their demand and access level, unaware of the DBMS, use predefined queries

sophisticated users – have complex requirements and queries, know the structure of the DBMS, engineers, scientists…

casual users – occasional users, need different data every time they come, use sophisticated queries…

Users …2. Support personnel - manage the database

starting from its creation. Database Administrator - responsible to

manage the database and the DBMS, authorize access, determine HW and SW resources,

Database Designer – identifies the data to be stored and the structure of the database.

System Administrator – responsible for the entire computer system of the organization.

DBMS• Stands for Database Management

System• A DBMS is a software package forproviding a systematic method for

creating, updating, storing, retrieving data in a database.

controlling data access, enforcing data integrity, managing concurrency control, and recovery.

Purposes of DBMS• Concurrency control• Data processing –

creating ,updating, modifying….• Authorization service• Integrity services• User interfaces

End

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