CS 338 Databases and Database Users INTRODUCTION

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1 CS 338 Databases and Database Users INTRODUCTION Bojana Bislimovska Winter 2017

2 Outline Introduction An example Characteristics of the database approach Actors on the scene Workers behind the scene When not to use a DBMS

3 Data

4 Diversity 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.

5 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

6 Database 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.

7 Database 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

8 Database 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

9 DBMS 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

10 DBMS 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

11 Database System Database and DBMS software => Database system

12 Example Restaurant database

13 Used in pre-dbms databases File Processing 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

14 Characteristics of the Database Approach 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

15 Actors on the Scene 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

16 Actors on the Scene 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

17 Actors on the Scene 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

18 Workers behind the Scene 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)

19 When Not to Use a DBMS 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

Chapter 1. Types of Databases and Database Applications. Basic Definitions. Introduction to Databases

Chapter 1. Types of Databases and Database Applications. Basic Definitions. Introduction to Databases Chapter 1 Introduction to Databases Types of Databases and Database Applications Numeric and Textual Databases Multimedia Databases Geographic Information Systems (GIS) Data Warehouses Real-time and Active