introduction to DBMS

POPULAR DBMS SOFTWARES

1. MySQL 2. Microsoft Access 3. Oracle 4. FoxPro 5. IBM DB2 6. Microsoft SQL Server etc. 7. postgreSQL

users of dbms

1.APPLICATION PROGRAMMERS 2.DATABASE ADMINISTRATORS END-USERS

DISADVANTAGE OF DBMS

1.Cost of Hardware and Software of a DBMS is quite high which increases the budget of your organization. 2.Most database management systems are often complex systems, so the training for users to use the DBMS is required. 3. Some organizations, all data is integrated into a single database which can be damaged because of electric failure or database is corrupted on the storage media. 4.Use of the same application at a time by many users sometimes lead to the loss of some data.

Advantages of DBMS

1.REDUCED REDUNDANCY: • Remove duplicates/no repetition of the data. • Unique data can be maintained. Since data is not repeated we can say that redundancy is reduced.

Data Back up and Recovery

A DBMS must provide facilities for recovering from hardware or software failures. • The backup and recovery subsystem of the DBMS is responsible for recovery. • For example, if the computer system fails in the middle of a complex update program, the recovery subsystem is responsible for making sure that the .database is restored to the state it was in before the program started executing.

data base

A database is an organized collection of structured information, or data, typically stored electronically in a computer system. They are logically related.

data

COMPUTER DATA IS THE INFORMATION PROCESSED OR STORED BY A COMPUTER.

binary data

Computer data is a bunch of ones and zeros, known as binary data.It can be created, processed, saved, and stored digitally.

2.DATABASE ADMINISTRATORS

DATABASE ADMIN IS RESPONSIBLE FOR MANAGING THE ENTIRE DBMS SYSTEM. HE/SHE IS CALLED DATABASE ADMIN OR DBA.

REDUCED INCONSISTENCY

Data mismatch can be avoided. In a database approach the address is stored in the general office only. Data redundancy leads to data inconsistency especially when data is to be updated. When the data is not repeated or there is no redundancy and inconsistency can also be reduced. Data inconsistency occurs due to the same data items that appear in more than one file do not get updated simultaneously in each and every file.

data inconsistency

Data redundancy leads to data inconsistency especially when data is to be updated. Data inconsistency occurs due to the same data items that appear in more than one file do not get updated simultaneously in each and every file. This results in two different designations of an employee at the same time. Over the period of time, such discrepancies degrade the quality of information contain in the data file that affects the accuracy of reports.

Data Security

Data security features of DBMS allows only authorized users to access the confidential and necessary data of an organization .DBMS provides username and password to users to use their databases.

Advantages of storing data in binary form

Easy transfer of data from one computer to another using a network connection or various media devices. Data does not deteriorate over time or lose quality after being used multiple times.

Less Secure

Files can easily be moved or transferred or even renamed. With all documents being easily accessible, this makes it easy for a potential hacker to find documentation that is stored in one particular place.

file base system

In a file base system all the files are independent and isolated. • We repeat the data in all the files.

database approach

In database approach data is centralized and not repeated in all tables. • Information about student name, class ,mob no is stored only once in general office • If library needs it that can be accessed from general office by joining the tables.

Data Sharing

It allows the same data to be shared among multiple users thereby facilitating the end users to access and manage the data in an efficient manner. • Many remote users can also access the database simultaneously and share the data between themselves.

data redundancy

Since each application has its own data file, the same data may have to be recorded and stored in many files. The result is unnecessary duplicate or redundant data items. This redundancy requires additional or higher storage space, costs extra time and money, and requires additional efforts to keep all files up to- date.

Lack of Data Integration

Since independent data file exists, users face difficulty in getting information on any ad hoc query that requires accessing the data stored in many files. In such a case complicated programs have to be developed to retrieve data from every file or the users have to manually collect the required information.

1.APPLICATION PROGRAMMERS:

THE APPLICATION PROGRAMMERS WRITE PROGRAMS IN VARIOUS PROGRAMMING LANGUAGES TO INTERACT WITH DATABASES

END-USERS

THE END USERS ARE THE PEOPLE WHO INTERACT WITH DATABASE MANAGEMENT SYSTEM.THEY CONDUCT VARIOUS OPERATIONS ON DATABASE LIKE RETRIEVING,UPDATING,DELETING ETC.

Limited Data Sharing

There is limited data sharing possibilities with the traditional filesystem. Each application has its own private files and users have little choice to share the data outside their own applications. Complex programs required to be written to obtain data from several incompatible files.

Decentralization : Poor Data Control

There was no centralized control at the data element level, hence a traditional file system is decentralized in nature.

how is comp data processed and stored

comp data is processed in the cpu and stored in the form of files and folders on the computers hard disk

Data Integrity

• Integrity of data means that data in database is always accurate, such that incorrect information cannot be stored in database. In order to maintain the integrity of data, some integrity constraints are enforced on the database • Example In the university database class having only BTech, MTech, MSc, BCA, BBA and BCOM classes. But if user enters the class MCA, then this incorrect information must not be stored in database and must be prompted that this is an invalid data entry. • In order to enforce this, the integrity constraint must be applied to the class attribute .But, in case of file system constraint must be enforced on all the application separately (because all applications have a class field).