Architecture of DBMS and RDBMS

DBMS AND RDBMS

DBMS ARCHITECTURE:

A data base is an organized collection of information. It consists of all the files in an organized manner therefore database is a structured and integrated system to facilitate upto-date information. Technically, a data base consist all the files in the data base management system as an integral part.

A DBMS requires to perform variety of operations, when the user requests the system to perform operations, which are as follows…..

• Adding new records  into the data base.
• Modifying the data in the existing files
• Retrieving data from the files
• Deleting the data from the files
• Searching the data from the files, upon a condition
• Removing the files from the database

A data base whose over all purpose is, to store information and allow the users to retrieve  and  update the information. 

DBMS is divided into four main components such as,

1.   Data

2.   Hard ware

3.   Soft ware

4.   Users

Data:

Data is referred to what is actually stored in the database  & information refers to the meaning of that data as understood by the users.  The data base systems are available on the machines that ranges all the way from a small p.c to the large mainframes this facility  is provided by any given system is determined by the size & power of the machine. A multi- user system is a system in which many users can access the data at the same time.

HARDWARE:

Hard ware components of a system consists of

1.   Hardware processor with a database system software

2.   Secondary storage devices

3.   Typically the magnetic discs & magnetic tapes, used to hold the data together with I/o devices, device controllers etc. 

SOFTWARE:

The data is physically stored in the database & the users of the system is a layer of the software known as DBMS OR database server.

All the requests to accesses the database are handled by DBMS.

USERS:

The users are broadly classified into  3 types ,

1. APPLICATION PROGRAMMERS

2. END USERS

3. DATABASE ADMINISTRATORS

The application users are responsible for writing  database application programs in some programming languages such as COBOL,C,C++ etc. Such programs  access the database by issuing the appropriate request.

The end users are those who access the database interactively. The database system has built in applications called QUERY LANGUAGE processors by which the users can access the database through a request by using commands.

The database administrator is an associated data administration functions. 

Thus, the advantage of database systems are, used due to its,

1.   Speed

2.  Accuracy

3.  Up to-date information

4.  Compactness

5.  Protection

6.  Reliability and

7.  Security

ADVANTAGES OF  DATABASE:

1.     A  DATA BASE  CAN  BE  SHARED:

Sharing means not only existing application that can  share the data Iin a database  system but also a new application can be developed to operate against the same data.

2.     REDUNDANCY  CAN  BE  REDUCED:

Redundancy means, repetition or duplication of data.  In non-database systems, each application has its own private fields. This fact will lead a redundancy in the stored data.  This resultant waste is stored & it may lead to  inconsistency.

3.    INCONSISTENCY CAN BE AVOIDED:

The DBMS is not aware of the duplication of the data.  When there will be an occasion of redundancy and therefore, can’t be updated in the database when you modify the data once. Thus the data base is said to be inconsistent.

4.    TRANSACTION SUPPORT CAN BE PROVIDED:  

A transaction is a logical unit of work involving several database operations For example, the transfer of cash account from one account to another account.

5.    INTEGRITY CAN BE MAINTAINED: 

     

Integrity means ensuring the correct data in a database.  Integrity problem can arise only if redundancy exists in the stored data.

6.    SECURITY CAN BE ENFORCED:

The data base manager or DBA can ensure that the only means of accessing the database is through proper channel & hence you can define the security constraints whenever an access is attempted to reach the sensitive data.

7.    CONFLICTING REQUIREMENTS CAN BE BALANCED:

When you know the overall requirements of the organization, the DBA can be structured in such a way so as to provide overall services

8.    STANDARDS CAN BE ENFORCED:

With the central control of database, the DBA can ensure that all the applicable standards are observed in the representation of data.

9.    DATABASE ADMINISTRATION:

The DBA decides what data should be stored in the data & the policies for maintaining the database.  An example of such policy in dealing with the data is security. A DBA is responsible for ensuring a system that operates with an adequate performance & provide a variety of other technical services for most important applications.

RDBMS:

A data base is a persistent & meaningful data .A relational database management is a dbms that is based on the relational model introduced by Dr. EDGER F CODD. A  RDBMS  stores the data in the form  of related tables .RDBMS software’s are powerful  because they require few assumptions about how a data is related  & the way how a data ia extracted from the database . As a result the same data can be viewed in many different ways.

The common language to access the data in a database is ‘structured query language’ (SQL) and hence, it is an interface to RDBMS .SQL can be pronounced as, SEQUEL which is developed in the year 1970 by IBM. It has become the standard language used to inter act the RDBMS software’s such as ORACLE, SYBASE etc.