Download Introduction to Database Management

CS 338
Databases and Database Users
INTRODUCTION
Bojana Bislimovska
Winter 2017
Major research
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Outline
Introduction
An example
Characteristics of the database approach
Actors on the scene
Workers behind the scene
When not to use a DBMS
Major research
Data
Diversity
of
Data
Major research
• 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
Database
Management
System
Major research
Database Management System (DBMS)
General-purpose software system that facilitates the processes of
defining, constructing, manipulating and sharing databases among
various users and applications.
Database
Management
System
Major research
• 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
Database
Management
System
Major research
• 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
DBMS
Features
Major research
• 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
DBMS
Features
Major research
• 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
Database
System
Major research
Database and DBMS software => Database system
Major research
Example
Restaurant database
File
Processing
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
Characteristics of the Database
Major research 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
Actors
on
the
Scene
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
Workers
behind
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)
When
Not
to
Use
a
DBMS
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