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 them Stores the result Displays 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Why not text files, Spreadsheets• Data integrity• Redundancy• Outdated data• Data size• Retrieval• Searching• Filtering• Protecting data from unauthorized use• Protecting data from becoming corrupt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