Database Technology: Achievements and Opportunities Dr M Saraee Dept. of Electrical and Computer Eng

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Database TechnologyAchievements and
OpportunitiesDr M Saraee Dept. of Electrical
and Computer Engineering Isfahan University of
Technology
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Outline of Discussion

• Why do we need databases
• Database Systems Past, Present and Future
• Overview of New Approaches

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File-based Systems
A collection of application programs that perform
services for the end users (e.g. reports). Each
program defines and manages its own data.
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Database / DBMS

• Database A shared collection of logically
  related data (and a description of this data),
  designed to meet the information needs of an
  organisation.
• DBMS A software system that enables users to
  define, create, and maintain the database and
  which provides controlled access to this database.

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Database Management System (DBMS)
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Why do we need database management systems?

• A Database Management System (DBMS) is a tool
  that allows to store, modify and query data.

However, we can store, modify and query data in a
text file! What can a DBMS do that we cant do
with the text file solution.
File-based solution to manage data, stick it all
in a text file!
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Enforcing Constraints

• With the File-based Systems there is no way to
  enforce integrity constraints on the data. In
  other words people can put bad data into the text
  file.
• In contrast, a DBMS allows us to enforce all
  kinds of constraints. This really helps (but does
  not guarantee) that our data is correct.

A typo gives Roberta Wickham a GPA of 44.00
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Scalability

• The File-based Systems old method, might work
  for small datasets. What happens when we have big
  datasets
• Most real world datasets are so large that we
  can only have a small fraction of them in main
  memory at any time, the rest has to stay on disk.
• Even if we had lots of main memory, with 32 bit
  addressing we can only refer to 4GB of data!

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Query Expressiveness

• The File-based Systems would allow us to search
  for keywords or certain numbers (slowly).
• With a DBMS we can search with much more
  expressive queries. For example I can ask.. Find
  all students whose GPA is greater than 2.5, and
  who dont own a phone or what is the average
  GPA of the students

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Query Expressiveness II

• We could write some program that might allow
  more expressive queries on my text file, but it
  would tied into the structure of our data and the
  operating system etc..
• With a DBMS we are completely isolated from the
  physical structure of our data. If we change the
  structure of our data (by adding a field, for
  example) or moving from a PC to a Mac, nothing
  changes at the front end!

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Different Views

• The File-based System only allows one view of
  the data.
• With a DBMS we can arrange for different people
  to have different views of the data. For example,
  I can see everything, a student can see only
  his/her data, the TA can see

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Concurrency

• Suppose we leave my text file on UNIX account,
  and weI log in and begin to modify it at the same
  time our TA is modifying it!
• A DBMS will automatically make sure that this
  kind of thing cannot happen.

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Security

• Suppose I leave my text file on UNIX account,
  and a student hacks in and changes their grades
• A DBMS will allow multiple levels of security.

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Crash Recovery

• Suppose I am editing my text file and the system
  crashes!
• A DBMS is able to guarantee 100 recovery from
  system crashes.

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Roles in the Database Environment

• Data Administrator (DA)
• Database Administrator (DBA)
• Database Designers (Logical and Physical)
• Application Programmers
• End Users (native and sophisticated)

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Database Systems Achievements

• Relational Database Systems
• Transaction Management
• Distributed Relational Database Systems

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Database Systems Current Research

• Object-Oriented DBMS
• Object-Relational DBMS
• Support for New Data Types
• temporal data
• spatial data
• Transaction Processing

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Technology vs Functionality Matrix
Functionality
Active
Multimedia
Geographical
Temporal
SpatioTemporal
Technology
Relational
Object-Oriented
Interoperable
Combine functionality from existing technology
Add functionality to existing technology
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Database Systems New Applications

• Earth Observation Data
• Electronic Commerce
• Health-Care Information Systems
• Digital Publishing
• Collaborative Design

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Earth Observation Data

• The Earth Observing System (EOS) will gather
  data about the atmosphere, oceans and land.
• NASA satellites have been launched from 1998
  onwards
• Data transmission is estimated to be 1/3 petabyte
  per year (1PB 109 MB1015 bytes)
• EOS Data and Information System (EOSDIS) will
  support on-line access and maintenance of EOS
  data.

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Electronic Commerce

• Needs support for browsing of catalogs and
  electronic purchasing of goods
• Large number of consumers and suppliers
• Database challenges
• heterogeneous distributed information sources
• distributed authentication and fund transfers

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Health-Care Information Systems

• Improve quality and quantity of health care
• Needs support for medical records across
  hospitals, medical offices and insurance offices
  and across countries
• Collection of historical information about a
  patient
• Database challenges
• integration of heterogeneous legacy information
• access control to preserve confidentiality of
  medical records
• intelligent interfaces to be used by health-care
  professionals

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Distributed Databases

• A distributed database system consists of a
  collection of sites, connected together via some
  kind of communications network, in which
• each site is a database system in its own right,
  but
• the sites have agreed to work together (if
  necessary), so that a user at any site can access
  data anywhere in the network exactly as if the
  data was all stored at the user's own site
• Fundamental principle of distributed databasesa
  distributed system should look exactly like a
  nondistributed system

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Active Databases

• Relational Databases are passive
• They execute queries or database operations only
  when explicitly requested to do so by a user or
  an application program.
• Active Databases are reactive
• They monitor conditions defined on states of the
  database, and then, once these conditions occur,
  they invoke specified actions.

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Active Database Components

• The rule base
• WHEN event IF condition THEN action
• The database
• The inference mechanism (rule manager)
• The user interface

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Information Systems and Time
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Why Time Modelling?

• Historical queries about past status
• Trend analysis
• Representation of retroactive or proactive
  changes
• Version control and design management
• Scheduling and planning requirements

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Time and IS Modelling

• What was the salary of John Smith last year
• What was the business policy for the Product
  Ordering process under the previous managing
  director
• What is the history of the Product Promotion
  strategy?

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Conclusions

• Knowledge Representation and Manipulation within
  a computer is the single most important challenge
  for IS
• Databases are the main focus of this work and
  they are the most widely available technology
  outside operating systems
• The next few years will see another rapid
  expansion of this area

Information Management