INFORMATION SYSTEM 2011
What is a Database?
A collection of related pieces of data:
 Representing/capturing the information about a real-world
Enterprise or part of an enterprise.
 Collected and maintained to serve specific data management
Needs of the enterprise.
 Activities of the enterprise are supported by the database and
Continually update the database.
An Example
University Database:
Data about students, faculty, courses, researchLaboratories, course registration/enrollment etc.
Reflects the state of affairs of the academic aspects of the
University.
Purpose: To keep an accurate track of the academic
Activities of the university.
Database Management System (DBMS)
A general purpose software system enabling:




Creation of large disk-resident databases.
Posing of data retrieval queries in a standard manner.
Retrieval of query results efficiently.
Concurrent use of the system by a large number of users
in a consistent manner.
 Guaranteed availability of data irrespective of system failures.
A database management system (DBMS) is a collection of computer programs that
controls databases in every way–creation, maintenance and use of the database.
Specifically, it enables an organization to hand power and control of the database into
the hands of the administrators and other specialists who understand the database.
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One of the most important aspects of a DBMS is the end user. A DBMS ensures that
information is presented to users from the database in a logical fashion.
Organization of a Database Management System
A
DBMS is categorized based on the data structure or type. Like types of data
stick together. When an application program sends a request for data, the
DBMS accepts it, interprets it and then sends an instruction to the operation
system to initiate the transfer of the data. The data is transferred through the DBMS and
the original application gets what data it needs.
The use of a DBMS also allows for information
systems to be changed more easily. This is especially
important in the IT world because information
requirements change on a very regular basis. As time
goes on and more needs are required, new categories
of data are added to the database. More importantly,
these categories are added without any disruption to
the system.
DBMS is typically found at the very center of most
database applications.
Principles of Modern Database Systems
T
he area of systems for handling large quantities of data is expanding very rapidly.
Classical query languages were optimized for queries to data persistently stored
on disk, while modern Data Stream management Systems (DSMSs) permit high
performance queries directly on steams of numerical measurements. Classical
relational Database Management Systems (DBMSs) could handle only well-structured
tabular data. Modern DBMSs can also handle complex Object-Oriented data, and semistructured data such as, e.g., text, XML, numerical, temporal, and spatial data.
Furthermore queries to classical databases were very simple while modern DBMSs
permit numerical data analysis over the database. Classical databases had a central
client-server architecture while modern databases require the ability to handle many
cooperating and distributed databases and utilize new hardware infrastructures, e.g. the
Grid.
The purpose of the course is to give an overview of the principles, theories and
realizations of the state-of-the-art within the field of database technology both within
research and commercially. There will be an emphasis on modern streamed and
extensible database technology (beyond classical relational databases) for managing
new kinds of heterogeneous data representations such as, semi-structured, spatial, or
numerical data. Attendees can get one extra point by utilizing taught technology on
some of their own problems.
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Components of DBMS
There are five main components of DBMS. These components are:
DBMS Engine: Accepts the request from the subsystems of DBMS. Converts them into
physical equivalents and then accesses the database.
Data Definition Subsystem: Create and maintain data dictionary. Define structure of the
files within the DB.
Data Manipulation Subsystem: Add, change and delete information in a database.
Application Generation Subsystem: Helps develop transaction-intensive applications.
Data Administration Subsystem: Manages the overall database environment. This
includes security, backup and recovery and change management.
DBMS Trends
B
ecause the database has become so streamlined and effective, things have
moved from physical applications to Web services. For example, Google’s GMail
would not be possible without a very smooth, effective database system. DBMS,
therefore, made it possible for this to happen. As more is done on the Internet and there
is greater demand for storage capabilities, DBMS will continue to be in demand.
Because of this, there will always be a need for more development and more growth.
How Database Approach Differs from Traditional File
System Concepts?
A database is a collection of interrelated data's stored in a database server; these data's
will be stored in the form of tables. The primary aim of database is to provide a way to
store and retrieve database information in fast and efficient manner.
The fundamental characteristic of database approach is that the database system not
only contains data's but it contains complete definition or description of the database
structure and constraints. These definitions are stored in a system catalog, which
contains the information about the structure and definitions of the database.
Database can be used to provide persistent storage for program objects and data
structures that resulted in object oriented database approach. Traditional systems
suffered from impedance mismatch problem and difficulty in accessing the data, which
is avoided in object oriented database system. Database can be used to represent
complex relationships among data's as well as to retrieve and update related data easily
and efficiently.
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Modern Approaches
M
ontreal, Canada (Press Exposure) December 09, 2009 -- MS SQL database
repair software is SQL repairing tool. It efficiently repairs the database of
damaged SQL. In today’s life SQL is used more for preparing a database. Thus
the chance of corruption also reaches the hike. The reasons which can lead to damage
the SQL server are abnormal shut down of server computer, power failure, defects of
server computer etc.
Stored procedures, tables, trigger, views everything is easily repaired and recovered. As
SQL have primary keys, foreign keys and unique keys then they are also corrupted
when hazard while running SQL arrives. Deleted records and section wise damaged
reports are also recovered by MS SQL database repair software. When the software is
executed then re-building batch of database is created by which we can comfortably
work with created database.
Some of the features of MS SQL database repair are as follows:
The software extracts the data from damaged SQL database. Where there the retrieved
files are saved, script files are also saved. Formatted records can be saved in the
individual script SQL file. Server backup files are also recovered. Procedures, tables
and views etc. recovery is done by MS SQL database repair. Recovery of foreign,
primary, unique key is done.
The MS SQL database repair software is available in for trial version too apart from
paying version. If users have licensed software then he can update the features of SQL
database repair. In the version chose content preview of damaged file is also displayed.
Today, for the business having no intermission, MS SQL database re[air software can
be used.
The Evolution of Database Technology
This is a joint meeting with the UK Chapter of DAMA International and we are privileged
to have Charlie Bachman with us for the day. Charlie Bachman will presenting his views
on the future of database at the end of the day, but before that we will have
presentations from Bill Olle, one of our committee members who has been involved in
database development and database standards for many years, Stephen Brobst, the
Chief Technology Officer of Teradata, and, hopefully, a representative from one of the
mainstream database vendors. Charles Bachman was appointed a Distinguished Fellow
of the British Computer Society in 1977 and in 1973 was also the recipient of the ACM
prestigious Turing award. These awards recognize his early work during the 1950s on
network database management and also his development of the use of Bachman
diagrams for analyzing and designing database structures. In 1983 he founded
Bachman Information Systems. In total Charlie spent over 44 years in the software
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development industry. There is no charge for attendance to members of the DMSG or
DAMA UK, but pre-registration is required. The fee for those who are BCS members but
are not registered as members of the DMSG is £20 and the fee for all others is £30.
Registration, with tea and coffee, will start at 9.30 am and a buffet lunch will be served.
Database Management System (DBMS)
D
BMS is a software package with computer that controls the creation,
maintenance, and the use of a database. It allows organizations to conveniently
develop databases for various applications by database administrators (DBAs)
and other specialists. A database is an integrated collection of data records, files, and
other database objects. A DBMS allows different user application programs to
concurrently access the same database. DBMSs may use a variety of database models,
such as the relational model or object model, to conveniently describe and support
applications. It typically supports query languages, which are in fact high-level
programming languages, dedicated database languages that considerably simplify
writing database application programs. Database languages also simplify the database
organization as well as retrieving and presenting information from it. A DBMS provides
facilities for controlling data access, enforcing data integrity, managing concurrency
control, recovering the database after failures and restoring it from backup files, as well
as maintaining database security.
What Do You Need for Transaction Processing?
Data processing folks like to talk about the "ACID test" when deciding whether or not a
database management system is adequate for handling transactions. An adequate
system has the following properties:
Results of a transaction's execution are either all committed or all rolled back. All
changes take effect, or none do. That means, for Joe User's money transfer, that both
his savings and checking balances are adjusted or neither are. For a Web content
management example, suppose that a user is editing a comment. A Web script tells the
database to "copy the old comment value to an audit table and update the live table with
the new text". If the hard drive fills up after the copy but before the update, the audit
table insertion will be rolled back.
Consistency
The database is transformed from one valid state to another valid state. This defines a
transaction as legal only if it obeys user-defined integrity constraints. Illegal transactions
aren't allowed and, if an integrity constraint can't be satisfied then the transaction is
rolled back. For example, suppose that you define a rule that postings in a discussion
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forum table must be tied to a valid user ID. Then you hire Joe Novice to write some
admin pages. Joe writes a delete-user page that doesn't bother to check whether or not
the deletion will result in an orphaned discussion forum posting. The DBMS will check,
though, and abort any transaction that would result in you having a discussion forum
posting by a deleted user.
Isolation
The results of a transaction are invisible to other transactions until the transaction is
complete. For example, if you are running an accounting report at the same time that
Joe is transferring money, the accounting report program will either see the balances
before Joe transferred the money or after, but never the intermediate state where
checking has been credited but savings not yet debited.
History of DBMS
History
Databases have been in use since the earliest days of electronic computing. Unlike
modern systems which can be applied to widely different databases and needs, the vast
majority of older systems were tightly linked to the custom databases in order to gain
speed at the expense of flexibility. Originally DBMSs were found only in large
organizations with the computer hardware needed to support large data sets.
1960sNavigationalDBMS
as computers grew in capability, this trade-off became increasingly unnecessary and a
number of general-purpose database systems emerged; by the mid-1960s there were a
number of such systems in commercial use. Interest in a standard began to grow, and
Charles Bachman, author of one such product, Integrated Data Store (IDS), founded the
"Database Task Group" within CODASYL, the group responsible for the creation and
standardization of COBOL. In 1971 they delivered their standard, which generally
became known as the "Codasyl approach", and soon there were a number of
commercial
products
based
on
it
available.
IBM also had their own DBMS system in 1968, known as IMS. IMS was a development
of software written for the Apollo program on the System/360. IMS was generally similar
in concept to Codasyl, but used a strict hierarchy for its model of data navigation instead
of Codasyl's network model. Both concepts later became known as navigational
databases due to the way data was accessed, and Bachman's 1973 Turing Award
presentation was The Programmer as Navigator. IMS is classified as a hierarchical
database. IDS and IDMS, both CODASYL databases, as well as CINCOMs TOTAL
database
are
classified
as
network
databases.
1970s
Relational
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Edgar Codd worked at IBM in San Jose, California, in one of their offshoot offices that
was primarily involved in the development of hard disk systems. He was unhappy with
the navigational model of the Codasyl approach, notably the lack of a "search" facility
which was becoming increasingly useful. In 1970, he wrote a number of papers that
outlined a new approach to database construction that eventually culminated in the
groundbreaking A Relational Model of Data for Large Shared Data Banks.
linked
together
In this paper, he described a new system
for storing and working with large
databases. Instead of records being stored
in some sort of linked list of free-form
records as in Codasyl, Codd's idea was to
use a "table" of fixed-length records. A
linked-list system would be very inefficient
when storing "sparse" databases where
some of the data for any one record could
be left empty. The relational model solved
this by splitting the data into a series of
normalized tables, with optional elements
being moved out of the main table to where
they would take up room only if needed.
In the relational model, related records are
with
a
"key".
Just as the navigational approach would require programs to loop in order to collect
records, the relational approach would require loops to collect information about any
one record. Codd's solution to the necessary looping was a set-oriented language, a
suggestion that would later spawn the ubiquitous SQL. Using a branch of mathematics
known as tuple calculus, he demonstrated that such a system could support all the
operations of normal databases (inserting, updating etc.) as well as providing a simple
system for finding and returning sets of data in a single operation.
End1970sSQLDBMS
IBM started working on a prototype system loosely based on Codd's concepts as
System R in the early 1970s. The first "quickie" version was ready in 1974/5, and work
then started on multi-table systems in which the data could be broken down so that all
of the data for a record (much of which is often optional) did not have to be stored in a
single
large
"chunk".
Many of the people involved with INGRES became convinced of the future commercial
success of such systems, and formed their own companies to commercialize the work
but with an SQL interface. Sybase, Informix, Nonstop SQL and eventually Ingres itself
were all being sold as offshoots to the original INGRES product in the 1980s.
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REFERENCES
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
Drucker, P.F. 1993. Post-Capitalist Society. New York: Harper Business.
Freeman, C. 1992. The Economics of Hope: Essays on Technical Change,
Economic Growth and the Environment. London: Pinter.
Sousa, L.J. 1992. Toward a new materials paradigm. Minerals Issues
(December). Washington, D.C.: U.S. Bureau of Mines.
U.S. Department of Commerce. 1996. Service Industries and Economic
Performance. Washington, D.C.: U.S. Department of Commerce.
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