Data Base Management System
Organizations use large amounts of data. A database management system (DBMS)
is a software tool that makes it possible to organize data in a database.
The standard acronym for database
management system is DBMS, so you will often see this
instead of the full name. system is
to store and transform data into information to support making decisions.
A DBMS consists of the following three
elements:
1. The physical database: the collection of files that contain the data
2. The database engine: the software that makes it possible to access and
modify the contents of the database
3. The database scheme: the specification of the logical structure of the
data stored in the database
While it sounds logical to have a DBMS
in place, it is worth thinking for a moment about the alternative. What would
the data in an organization look like without a DBMS? Consider yourself as the
organization for a moment, and the data are all the files on your computer. How
is your data organized? If you are like most typical computer users, you have a
large number of files, organized in folders.
You may have word processor documents,
presentation files, spreadsheets, photographs, etc. You find the information
you need based on the folder structure you have created and the names you have
given to your files. This is called a file system and is typical for individual computer
users.
Now consider the challenges you are
faced with. Have you ever lost a file? Have you had difficulty finding a file?
Probably. Perhaps you are using multiple computers and your files are located
in different physical locations. And when was the list time you created a
backup of all your files? You do back up, right?
You probably get the picture. A file
system is relatively simple, but it only works if you keep yourself very
organized and disciplined. Now consider an organization with 1,000 employees,
each with their own computer. Can you see some of the challenges when using a
file system? Do you really want critical financial data floating around the
offices as simple files on individual computers?
Functions of a DBMS
So what does a DBMS really do? It
organizes your files to give you more control over your data.
A DBMS makes it possible for users to
create, edit and update data in database files. Once created, the DBMS makes it
possible to store and retrieve data from those database files.
More specifically, a DBMS provides the
following functions:
- Concurrency: concurrent access
(meaning 'at the same time') to the same database by multiple users
- Security: security rules to
determine access rights of users
- Backup and recovery: processes to
back-up the data regularly and recover data if a problem occurs
- Integrity: database structure and
rules improve the integrity of the data
- Data descriptions: a data dictionary
provides a description of the data
Within an organization, the development
of the database is typically controlled by database administrators (DBAs) and other specialists. This ensures
the database structure is efficient and reliable.
Database administrators also control
access and security aspects. For example, different people within an
organization use databases in different ways. Some employees may simply want to
view the data and perform basic analysis. Other employees are actively involved
in adding data to the database or updating existing data. This means that the
database administrator needs to set the user permissions. You don't want
someone who only needs to view the database to accidentally delete parts of the
database.
Pros and Cons of DBMS
There are a number of benefits to using
a DBMS.
A DBMS provides automated methods to
create, store and retrieve data. It may take some time to set up these methods,
but once in place, a DBMS can make tedious manual tasks a thing of the past.
A DBMS reduces data redundancy and
inconsistency. Have you ever had different versions of the same file on your
computer hard drive? The same thing happens in organizations. A well-designed
DBMS will eliminate redundancy.
A DBMS allows for concurrent access by
multiple users, each with their own specific role. Some users only need to view
the data, some contribute to adding new data, while others design and manage
the database - all at the same time!
A DBMS increases security and
reliability. Database administrators are responsible for creating backups of
databases, controlling access and, in general, making sure it works the way it
was intended. Having one or more specialists control these tasks is a lot more
effective than having each computer user in an organization having to worry
about the security of their data.
A DBMS improves data quality. It is
easy to make mistakes when entering data. A DBMS makes it possible to set up
rules for the database. For example, when entering the phone number of a
customer you should not be entering text characters. A rule can be set up such
that you cannot enter text in the phone number field. Or think of specifying
the state where a customer resides. It is easier to select from a pre-defined
list of states than to have to type in the name.
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