EX NO: Study on RDBMS and its Application
DATE:
A Relational Database Management
System (RDBMS) is a collection of programs and capabilities that enable IT
teams and others to create, update, administer and otherwise interact with
a relational database. RDBMSes store data in the form of tables, with most
commercial relational database management systems using Structured Query
Language (SQL) to access the database. However, since SQL was invented
after the initial development of the relational model, it is not necessary for
RDBMS use.
The
RDBMS is the most popular database system among organizations across the world.
It provides a dependable method of storing and retrieving large amounts of data
while offering a combination of system performance and ease of implementation.
RDBMS vs. DBMS
In
general, databases store sets of data that can be queried for use in other
applications. A database management system supports the development,
administration and use of database platforms.
An
RDBMS is a type of database management system (DBMS) that stores data
in a row-based table structure which connects related data elements. An RDBMS
includes functions that maintain the security, accuracy, integrity and
consistency of the data. This is different than the file storage used in a
DBMS.
Other
differences between database management systems and relational database
management systems include:
·
Number
of allowed users. While a DBMS can only accept one user at a time, an
RDBMS can operate with multiple users.
·
Hardware
and software requirements. A DBMS needs less software and hardware than an
RDBMS.
·
Amount
of data. RDBMSes can handle any amount of data, from small to large, while
a DBMS can only manage small amounts.
·
Database
structure. In a DBMS, data is kept in a hierarchical form, whereas an
RDBMS utilizes a table where the headers are used as column names and the rows
contain the corresponding values.
·
ACID
implementation. DBMSes do not use the atomicity, consistency, isolation
and durability (ACID) model for storing data. On the other hand, RDBMSes base
the structure of their data on the ACID model to ensure consistency.
·
Distributed
databases. While an RDBMS offers complete support for distributed
databases, a DBMS will not provide support.
·
Types
of programs managed. While an RDBMS helps manage the relationships between
its incorporated tables of data, a DBMS focuses on maintaining databases that
are present within the computer network and system hard disks.
·
Support
of database normalization. An RDBMS can be normalized, but a DBMS
cannot.
Features
Of Relational Database Management Systems
Elements
of the relational database management system that overarch the basic relational
database are so intrinsic to operations that it is hard to dissociate the two
in practice.
The
most basic RDBMS functions are related to create, read, update and delete
operations -- collectively known as CRUD. They form the foundation of a
well-organized system that promotes consistent treatment of data.
The
RDBMS typically provides data dictionaries and metadata collections that are
useful in data handling. These programmatically support well-defined data
structures and relationships. Data storage management is a common capability of
the RDBMS, and this has come to be defined by data objects that range from
binary large object -- or blob -- strings to stored procedures. Data objects like this extend the scope of
basic relational database operations and can be handled in a variety of ways in
different RDBMSes.
The
most common means of data access for the RDBMS is SQL. Its main language
components comprise data manipulation language and data definition language statements. Extensions are available
for development efforts that pair SQL use with common programming languages,
such as the Common Business-Oriented Language (COBOL), Java and .NET.
RDBMSes
use complex algorithms that support multiple concurrent user
access to the database while maintaining data integrity. Security management,
which enforces policy-based access, is yet another overlay service that the
RDBMS provides for the basic database as it is used in enterprise settings.
RDBMSes
support the work of database administrators (DBAs) who must manage and monitor database activity.
Utilities help automate data loading and database backup. RDBMSes manage log
files that track system performance based on selected operational parameters.
This enables measurement of database usage, capacity and performance,
particularly query performance. RDBMSes provide graphical interfaces that help
DBAs visualize database activity.
While
not limited solely to the RDBMS, ACID compliance is an attribute of relational
technology that has proved important in enterprise computing. These
capabilities have particularly suited RDBMSes for handling business
transactions.
As
RDBMSes have matured, they have achieved increasingly higher levels of query
optimization, and they have become key parts of reporting, analytics and data warehousing applications for businesses as well.
RDBMSes are intrinsic to operations of a variety of enterprise applications and
are at the center of most master data management systems.
How RDBMS works
As
mentioned before, an RDBMS will store data in the form of a table. Each system
will have varying numbers of tables with each table possessing its own
unique primary key. The primary key is then used to identify
each table.
Within
the table are rows and columns. The rows are known as records or horizontal
entities; they contain the information for the individual entry. The columns
are known as vertical entities and possess information about the specific
field.
Before
creating these tables, the RDBMS must check the following constraints:
·
Primary
keys -- this identifies each row in the table. One table can only contain one
primary key. The key must be unique and without null values.
·
Foreign keys -- this is used to link two tables. The
foreign key is kept in one table and refers to the primary key associated with
another table.
·
Not
null -- this ensures that every column does not have a null value, such as an
empty cell.
·
Check
-- this confirms that each entry in a column or row satisfies a precise
condition and that every column holds unique data.
·
Data
integrity -- the integrity of the data must be confirmed before the data is
created.
Assuring
the integrity of data includes several specific tests, including entity,
domain, referential and user-defined integrity. Entity integrity confirms that
the rows are not duplicated in the table. Domain integrity makes sure that data
is entered into the table based on specific conditions, such as file format or range of values. Referential
integrity ensures that any row that is re-linked to a different table cannot be
deleted. Finally, user-defined integrity confirms that the table will satisfy
all user-defined conditions.
Advantages of relational
database management system
The
use of an RDBMS can be beneficial to most organizations; the systematic view of
raw data helps companies better understand and execute the information while
enhancing the decision-making process. The use of tables to store data also
improves the security of information stored in the databases. Users are able to
customize access and set barriers to limit the content that is made available.
This feature makes the RDBMS particularly useful to companies in which the
manager decides what data is provided to employees and customers.
Furthermore,
RDBMSes make it easy to add new data to the system or alter existing tables
while ensuring consistency with the previously available content.
Other
advantages of the RDBMS include:
·
Flexibility
-- updating data is more efficient since the changes only need to be made in
one place.
·
Maintenance
-- database administrators can easily maintain, control and update data in the
database. Backups also become easier since automation tools included in the
RDBMS automate these tasks.
·
Data
structure -- the table format used in RDBMSes is easy to understand and provides
an organized and structural manner through which entries are matched by firing
queries.
On
the other hand, relational database management systems do not come without
their disadvantages. For example, in order to implement an RDBMS, special
software must be purchased. This introduces an additional cost for execution.
Once the software is obtained, the setup process can be tedious since it
requires millions of lines of content to be transferred into the RDBMS tables.
This process may require the additional help of a programmer or a team of data
entry specialists. Special attention must be paid to the data during entry to
ensure sensitive information is not placed into the wrong hands.
Some
other drawbacks of the RDBMS include the character limit placed on certain
fields in the tables and the inability to fully understand new forms of data --
such as complex numbers, designs and images.
Furthermore,
while isolated databases can be created using an RDBMS, the process requires
large chunks of information to be separated from each other. Connecting these
large amounts of data to form the isolated database can be very complicated.
Uses of RDBMS
Relational
database management systems are frequently used in disciplines such as
manufacturing, human resources and banking. The system is also useful for
airlines that need to store ticket service and passenger documentation
information as well as universities maintaining student databases.
Some
examples of specific systems that use RDBMS include IBM, Oracle, MySQL, Microsoft
SQLServer and PostgreSQL.
RDBMS Product History
Many
vying relational database management systems arose as news spread in the early
1970s of the relational data model. This and related methods were originally
theorized by IBM researcher E.F. Codd, who proposed a database schema, or logical organization, that was not
directly associated with physical organization, as was common at the time.
Codd's
work was based around a concept of data normalization, which saved file space on storage disk
drives at a time when such machinery could be prohibitively expensive for
businesses.
File
systems and database management systems preceded what could be called the RDBMS
era. Such systems ran primarily on mainframe computers. While RDBMSes also ran
on mainframes -- IBM's DB2 being a pointed example -- much of their ascendance
in the enterprise was in UNIX midrange computer deployments. The RDBMS was a
linchpin in the distributed architecture of client-server computing, which connected pools of stand-alone
personal computers to file and database servers.
Numerous
RDBMSes arose along with the use of client-server computing. Among the competitors
were Oracle, Ingres, Informix, Sybase, Unify, Progress and others. Over time,
three RDBMSes came to dominate in commercial implementations. Oracle,
IBM's DB2 and Microsoft's SQL Server, which was based on a design originally
licensed from Sybase, found considerable favor throughout the client-server
computing era, despite repeated challenges by competing technologies.
As
the 20th century drew to an end, lower-cost, open source versions of RDBMSes
began to find use, particularly in web applications.
Eventually,
as distributed computing took greater hold, and as cloud architecture became
more prominently employed, RDBMSes met competition in the form of NoSQL systems. Such systems were often specifically designed
for massive distribution and high scalability in the cloud, sometimes forgoing
SQL-style full consistency for so-called eventual consistency of
data. But, even in the most diverse and complex cloud systems, the need for
some guaranteed data consistency requires RDBMSes to appear in some way, shape
or form. Moreover, versions of RDBMSes have been significantly restructured for
cloud parallelization and replication.
