STRUCTURE OF DATABASE MANAGEMENT SYSTEM

WelcomeIn this Presentation we are going to discuss about the STRUCTURE OF DBMS.So, first of all let’s understand what does STRUCTURE means

So A Question Arises in our mind !

As we have saw how we can connect to the Database. But how is the database laid to process all user requests? Since it is responsible to store huge amount of data and is capable of handling multiple requests from users simultaneously, it should be arranged properly.

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These are the components responsible of maintaining The structure of DBMS :-

1) APPLICATION

2) END USER

3) DDL

4) DDL COMPILER

5) DML COMPILER

6) QUERY OPTIMIZER

7) DATA FILES

8) DATA DICTIONARY

9) DATA MANAGER

01. ApplicationsIt can be considered as a userfriendly web page where the userenters the requests. Here hesimply enters the details that heneeds and presses buttons to getthe data.

02.End UserThey are the real users of thedatabase. They can be developers,designers, administrator or theactual users of the database.

03. DDLData Definition Language (DDL) is a query fired to create database,schema, tables, mappings etc in the database. These are thecommands used to create the objects like tables, indexes in thedatabase for the first time. In other words, they create structure ofthe database.

04. DDL CompilerThis part of database isresponsible for processing theDDL commands. That meansthese compiler actually breaksdown the command into machineunderstandable codes. It is alsoresponsible for storing themetadata information like tablename, space used by it, numberof columns in it, mappinginformation etc.

05.DML Compiler When the user inserts, deletes,updates or retrieves the recordfrom the database, he will besending request which heunderstands by pressing somebuttons. But for the database towork/understand the request, itshould be broken down to objectcode. This is done by this compiler.One can imagine this as when aperson is asked some question,how this is broken down intowaves to reach the brain!

06. Query Optimizer

When user fires some request, he is

least bothered how it will be fired on the

database. He is not all aware of

database or its way of performance. But

whatever be the request, it should be

efficient enough to fetch, insert, update

or delete the data from the database.

The query optimizer decides the best

way to execute the user request which is

received from the DML compiler.

It has the real data stored in it.

It can be stored as magnetic

tapes, magnetic disks or

optical disks.

07. Data Files

It contains all the information about the

database. As the name suggests, it is

the dictionary of all the data items. It

contains description of all the tables,

view, materialized views, constraints,indexes, triggers etc.

08. Data Dictionary

8.1. Function of Data Dictionary

a) Defines the data element.

b) Helps in the scheduling.

c) Helps in the control.

d) Permits the various users who know which data is available and how can it be obtained.

e) Helps in the identification of the organizational data irregularity.

f) Acts as a very essential data management tool.

g) Provides with a good standardization mechanism.

h) Acts as the corporate glossary of the ever growing information resource.

i) Provides the report facility, the control facility along with the excerpt facility.

Stored Data Manager

1) This is also known as Database Control System. It is one the main

central system of the database. It is responsible for various tasks.

2) It converts the requests received from query optimizer to machine

understandable form.

3) It makes actual request inside the database. It is like fetching the

exact part of the brain to answer.

4) It controls concurrent access.

5) If there is multiple users accessing the database at the same time,

it makes sure, all of them see correct data.

Stored Data Manager

6) It helps to maintain consistency and integrity by applying the

constraints. That means, it does not allow inserting / updating / deleting

any data if it has child entry. Similarly it does not allow entering any

duplicate value into database tables.

7) It guarantees that there is no data loss or data mismatch happens

between the transactions of multiple users.

8) It helps to backup the database and recover data whenever required.

9) Since it is a huge database and when there is any unexpected

exploit of transaction, and reverting the changes are not easy, so

It maintains the backup of all data, so that it can be recovered.

End User

DML Compiler

Query Optimizer

DDL Compiler

Stored Data Manager

Data Files CompiledDML

DataDictionary

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