The Importance of Databases

scacchicgardenSoftware and s/w Development

Dec 13, 2013 (3 years and 10 months ago)

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PRESENTED BY:

LASONYA SHELBY

04/18/2010

LSTE 7309




The Importance of Databases

Relational Database


The term relational database was originally defined and coined by
Edgar Codd at IBM Almaden Research Center in 1970.



A relational database matches by using common characteristics found
within the data set. The resulting groups of data are organized and
are much easier for many people to understand.


Example: Real estate transactions in a town can be grouped by the year the


transaction occurred; or it can be grouped by the sale price of the transaction; or
it can be grouped by the buyer’s last name.



Relational database theory uses a set of mathematical terms, which
are roughly equivalent to SQL database terminology.



Relational Database contd.


Relational databases, as implemented in relational database
management systems, have become a predominant choice for the storage
of information in new databases used for financial records,
manufacturing and logistical information, and personnel data and much
more.



Relational Databases have been challenged by Object Databases, which
were introduced in an attempt to address the object
-
relational
impedance mismatch in relational database, and XML databases.



The three leading commercial relational database vendors are Oracle,
Microsoft, and IBM. The three leading source implementations are
MySQL, PostgreSQL, and SQLite.

Database Normalization


Normalization was first proposed by Codd as an integral part of the
relational model. It encompasses a set of best practices designed to
eliminate the duplication of data, which in turn prevents data
manipulation anomalies and loss of data integrity.



The most common form of normalization applied to databases are
called the normal forms.



Normalization is criticized because it increases complexity and
processing overhead required to join multiple tables representing what
are conceptually a single item.

Database Normalization contd.


Database normalization is also the process in which a database
structure is free from any uncertainties like update, insertion, and
deletion incidences.



In order to normalize a database it must be designed in the third
normal form. In the third normal form, all data will be secured, and
only certain areas of the table are subjected to any change.



There are three major problems encountered in database normalization
and they are: the update anomaly, the insertion anomaly, and the
deletion anomaly.

Database Applications


There are three types of applications and they are: Access, MySQL, and
Oracle.



Microsoft Office Access, previously known as Microsoft Access, is a
relational database management system from Microsoft that combines
the relational Microsoft Jet Database Engine with a graphical user
interface and software development tools.



Access stores data in its own format based on the Access Jet Database
Engine. It can also import or link directly to data stored in other Access
databases.


Database Applications contd.


Microsoft Access is used to create simple database solutions. Access
also includes a query interface, forms to display and enter data, and
reports for printing.



Microsoft offers a wide range of template databases within the
program and for download from their website. These options are
available upon starting Access and allow users to quickly use and
enhance a database with pre
-
defined tables, queries, forms, reports,
and macros.



Microsoft Access also offers the ability for programming to create
solutions using the programming language for Visual Basic for
Applications (VBA), which is similar to Visual Basic 6.0 (VB6) and
used throughout Microsoft Office Programs.

Database Applications contd.


The Oracle Database (commonly referred to as Oracle RDBMS or
simply as Oracle) is a relational database management system
(RDBMS) produced and marketed by Oracle Corporation. As of 2009,
Oracle remains a major presence in database computing.



Larry Ellison and his friends and former co
-
workers Bob Miner and Ed
Oates started the consultancy Software Development Laboratories
(SDL) in 1977. SDL developed the original version of the Oracle
software.



The Oracle RDBMS stores data logically in the form of tablespaces and
physically in the form of data files.

Database Applications contd.


Oracle databases control simultaneous access to data resources with
locks (alternatively documented as “enqueues”. The databases also
utilize “latches”
-

low
-
level serialization mechanisms to protect shared
data structures in the System Global Area.



Oracle database software comes in 63 language
-
versions including
regional variations such as American English and British English.
Variations between versions cover the names of days and months,
abbreviations, time
-
symbols such as A.M. and A.D., and sorting.



Oracle Corporation provides database developers with tools and
mechanisms for producing internationalized database applications:
referred to internally as “Globalization”.

Database Applications contd.


MySQL is a relational database management system which is an open
source database.



MySQL has unique storage engine architecture whose performance is
very high. It supports large number embedded applications which
makes it very flexible.



MySQL has stored procedures and views which allows the developer to
give a higher productivity, and allows transactions to be rolled back,
commit and crash recovery.

Database Applications contd.


MySQL can be used for both Windows and Linux. Managing database
includes adding, accessing, and processing data in a database.



Some of the advantages of MySQL are it is very highly efficient, open
source, highly secured since all password traffic is encrypted
connecting to a server, and it offers a high scalability in terms of size
and connectivity.



There are some disadvantages to MySQL which are: it does not support
a very large database size as efficiently, it does not support ROLE,
COMMIT, and Stored procedures in versions less than 5.0, and
transactions are not handled very efficiently.

Database Applications contd.


Many storage types are present in MySQL and they are: MyISAM,
memory storage, example storage, CSV storage, the BLACKHOLE
storage, and the NDCLUSTER.




MySQL is designed for a specific purpose which is to query data
contained in a relational database. MySQL is a set
-
based, declarative
query language, not an imperative language such as C or BASIC.
However, there are extensions to Standard SQL which add procedural
programming language functionality, such as control
-
of
-
flow
constructs.



Bibliography


www.wikipedia.org


www.oracle.com


www.answers.com


www.databaseguides.com