Winter 2016

Bojana Bislimovska

CS 338 Databases and Database Users

INTRODUCTION

Major research

• Introduction

• An example

• Characteristics of the database approach

• Actors on the scene

• Workers behind the scene

• When not to use a DBMS

Outline

Major research Data

Major researchDiversity of Data

• Types of available data Text data Multimedia data Data in Social Networks Weather data Scientific data Web data Sensor data Stock data Enterprise data etc.

Major research Database

• Database logically coherent collection of data with inherent meaning

Some aspect of the real world (miniworld)

Designed and populated with data for a specific purpose

It can be of any size or complexity

Major researchDatabase Management System

Database Management System (DBMS)

General-purpose software system that facilitates the processes of defining, constructing, manipulating and sharing databases among various users and applications.

Major researchDatabase Management System

• Database Management System (DBMS)

General-purpose software system that facilitates the processes of defining, constructing, manipulating and sharing databases among various users and applications.

Additional features:

• System protection against hardware or software malfunction

• Maintenance of a database system over time

Major researchDatabase Management System

• Database Management System (DBMS)

General-purpose software system that facilitates the processes of defining, constructing, manipulating and sharing databases among various users and applications.

• DBMS examples IBM’s DB2, Microsoft’s Access and SQL Server, Oracle, MySQL, SAP’s SQL

Anywhere

Major researchDBMS Features

• Defining a database Specify data types, structures and constraints

Stored in the form of a database catalog

Meta-data: information stored inside a catalog

• Constructing a database Storing data on a storage medium

• Manipulating a database Querying a database to retrieve specific data

Update database to reflect miniworld changes

Major researchDBMS Features

• Sharing a database Multiple users and programs access concurrently

Application programs access the database • send queries

Transaction• An atomic unit of queries and updates that must be executed as a whole

Major researchDatabase System

Database and DBMS software => Database system

Major researchExample

Restaurant database

Major research

• Used in pre-DBMS databases

• Each user defines and implements the files needed for a specific software application

• Data definition is part of the application programming

• Change of records structure requires change of file access programs

• As the application base grows many shared files

a multitude of file structures

a need to exchange data among applications

File Processing

Major research

• Database approach Self-describing nature of a database system

• Description of database structure => Catalog

Insulation between programs and data, and data abstraction• Conceptual representation of data (data model)

• Storage and implementation details hidden

Support of multiple views of data for different user types

Sharing data and multiuser transaction processing• Concurrency control of DBMS => correct execution of transactions

Characteristics of the Database Approach

Major research

• Database Administrators Authorize access to the database (DB)

Coordinate and monitor its use

Acquire software and hardware resources as needed

• Database Designers Understand requirements of database users

Identify data to be stored in the DB

Choose appropriate structures to represent the data

Actors on the Scene

Major research

• End Users Require access for querying, updating and generating

reports

Casual end users• Use sophisticated query interface

• Occassionaly access the DB, may ask different information each time

Naive or parametric end users• Constant query and update of the DB (canned transactions)

• e.g. Available through mobile apps

Sophisticated End Users• Familiarize with the DBMS features to implement their own

applications with specific requirements

Actors on the Scene

Major research

• End users Standalone Users

• Maintain personal databases by using ready-made program packages which inlcude menu and graphic-based interfaces

• System analysts Determine requirements of end users to develop

specifications for canned transactions

• Application programmers Implement these specifications as programs, maintain the

canned transactions

Actors on the Scene

Major research

• DBMS system designers and implementers Design and implement the DBMS modules and interfaces as a software

package

• Tool developers Design and implement tools that facilitate database modeling and

design, database system design

• Operators and maintenance personnel Responsible for hardware and software environment running and

maintenance (for the DB system)

Workers behind the Scene

Major research

• When there exist high overhead costs of using a DBMS

• Customized database applications are more desirable in the following cases: Simple, well-defined database applications are not expected to

change at all

Stringent, real-time requirements for some applications may not be met (reason: DBMS overhead)

No multiple users access to data

Embedded systems with limited storage capacity (DBMS would not fit)

• Examples CAD tools, GIS, communication and switching systems

When Not to Use a DBMS