Explain the various components of Database Management System. | RDBMS | 4th Semester | AKU | Allrounder SITA RAM SAHU

 

Components of DBMS

The database system consists of many components. Each component performs very significant tasks in the database management system environment. A database environment is a collective system of components that comprise and regulates the group of data, management, and use of data, which consist of software, hardware, people, techniques of handling database, and the data also. DBMS have several components. Below is a list of components within the database and its environment. The DBMS can be classified into five main components which are explained as follows:

• Hardware
• Software
• Data
• Procedures
• Database Access Language
• People

Component of database management system environment- 

Now, let us discuss in brief some points regarding all these components of DBMS as follows:

Hardware

• The hardware refers to the physical parts of the computer and It also includes some various storage devices like hard disk and input output devices like monitor, printer etc.
• Hardware is the most visible part of any information system: the equipment such as computers, scanners and printers that is used to capture data, transform it and present it to the user as output. 
• The hardware is the actual computer system used for keeping and accessing the database.
• Servers, which have large data storage capacities enabling users to share files and application software, although processing will typically occur on the user’s own machine.
• Workstations, which provide high-level performance for individual users in computationally intensive fields such as engineering.
• Databases run on the range of machines from micro computers to mainframes.  This also provides the interface between computers and the real world systems.
• When we run oracle or MySQL on our personal computer, then our computers hard disk, our keyboard with which we type in all the commands, our computers RAM, ROM all become a part of the DBMS hardware.

Software

• The main component of a Database management system is the software. 
• Software is a collection or set of programs, instructions that tell a computer what to do. Software comprises the entire set of programs, procedures, and routines associated with the operation of a computer system. A set of instructions that directs a computer’s hardware to perform a task is called a program, or software program.
• It also includes the database software, operating system, network software used to share the data with other users, and the applications used to access the data. 
• This software component is capable of understanding the Database Access Language and converts it into actual database commands to execute or run them on the database.
• This is the main component, as this is the program which controls everything. The DBMS software is more like a wrapper around the physical database, which provides us with an easy-to-use interface to store, access and update data.
• Some DBMS software examples include MySQL, PostgreSQL, Microsoft Access, SQL Server, FileMaker, Oracle, RDBMS, dBASE, Clipper, and FoxPro.

Data

• The word data covers the collection of facts stored in the database. Because data are the raw material from which information is generated
• Data stored in the database includes structure data, non-structural data, logical data.
• Structured data is highly specific and is stored in a predefined format, where unstructured data is a conglomeration of many varied types of data that are stored in their native formats. This means that structured data takes advantage of schema-on-write and unstructured data employs schema-on-read.
• Using a DBMS the database is first constructed, created or defined. After that the desired data is stored, accessed, and updated to the created database.
• The primary reason behind the introduction  of the database management system is to store and maintain the data within the database
• It is the most important component of the database management system. The typical database contains both the metadata(data about data) and the actual(operational) data.
• For example – when I store my name in a database, the DBMS will store when the name was stored in the database, what is the size of the name, is it stored as related data to some other data, or is it independent, all this information is Metadata.

Procedures

• Procedures refer to general instructions to use a database management system. This includes procedures to setup and install a DBMS, To login and logout of DBMS software, to manage databases, to take backups, generating reports etc.
• Procedures can be used for data validation, access control, or to reduce network traffic between clients and the DBMS servers. Extensive and complex business logic can be embedded into the subroutine, thereby offering better performance.
• The basic purpose of the procedures is to help guide users to the operation and management of database systems.
• Database Procedures are similar to Database Functions. The major difference is the way in which they are invoked – Database Functions can be used in the same way as for any other expression within SQL statements, whereas Database Procedures must be invoked using the CALL or EXEC statement, depending on the DBMS.
• In Enterprise Architect, Database Procedures can be model in one of two ways:
  • As individual objects (the default method)
  • As operations in a container

CREATE [OR REPLACE] PROCEDURE procedure_name (<Argument> {IN, OUT, IN OUT}    <Datatype>,...)  
IS 
  Declaration section<variable, constant> ; 
BEGIN 
  Execution section 
EXCEPTION 
  Exception section  
END

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