TERMINOLOGY

DATA

INFORMATION NEED OF INFORMATION QUALITIES OF INFORMATION FILE SYSTEM APPROACH LIMITATION OF FILE SYSTEM APPROACH DATABASE SYSTEM DATABASE SYSTEM ENVIRONMENT COMPONENTS OF DATABASE SYSTEM WHY STUDY DATABASES DATABASE MANAGEMENT SYSTEM(DBMS) FUNCTION OF DBMS STRUCTURE OF DBMS

It is a collection of meaningful facts which can be stored and processed by computers or humans. Ex Price, Phone no, addresses etc.

In terms of computing, data is defined as collection of facts that has been translated into the form that is more convenient to analyze or to do further calculation.

Data can be represented in the form of:

DATA

Words

Segments

Images

Sounds

Numbers

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Information is defined as the processed data which helps us in making decisions.

It is the intelligent form of data.

For Example:-

pay check, timetable, reports, merit list, bills etc.

The information is obtained by arranging data into meaningful form.

For Example:-

Marks obtained by students and their roll numbers form the data and their report card is the information which help us to make decision, which student stood at what rank in the class. BACK

Information is necessary for the people of the modern world because without proper information, it is very difficult to survive in the modern world.

One should keep himself aware of all the changes occurring in the society.

To keep the system up to date we need to gather information from various sources like television, internet, newspaper, radio, magazines etc.

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Must be meaningful Must be accurate and clear Should convey to the point relevant information Should confirm and correct the previous knowledge Should reach at proper time such that proper action is taken

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To computerize the manual way of storing data in the database was File System approach.

It is basically a collection of application programs that perform services to the end users

A file is a collection of records which contains logically related data known as fields

Multiple user access to the information is difficult to provide. This is due to poor coordination of application program.

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Data redundancy and inconsistency Data dependence Difficulty occur to get quick answers to simple queries Lack of data integrity and quality Difficult to share data Transaction problem Lack of security Concurrency problems

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Database:

A very large, integrated collection of data. A Database is a well organized collection of data that are related in a

meaningful way which can be accessed in different logical orders but are stored only once

The record of students maintained by your college is a useful database Models a real-world enterprise

◦ Entities (e.g., teams, games)

data1

data1

databaseorganizedRelated to

each other

Database BACK

Stored data base definitoin (META DATA)

Stored Database

Database System DBMS

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DATA BASE SYSTEM ENVIRONMENT

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The database system contains not only the database itself but also a complete definition or description of the database structure and constraint. This definition is stored in the system catalog.

The information stored in the catalog is called metadata that is the “data about the data”

An important property of database system is that the structure of data files is stored in the DBMS catalog separately from the access program.

We call this property as program-data-independence .

Due to this property we can change the structure of data files in the catalog but no need to change the programs.

The Purpose of the database system is to provide an environment that is both convenient an efficient to use in

Retrieving information from the database Storing information into the database

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DATAUser dataMeta dataApplication meta data

HARDWARE

SOFTWARE

USERS

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Data:-The data act as a bridge between the machine part and the user which directly

access it or access it through some application program. Data may be of different

types:

User Data:- It consist of a table of data called relation where columns are called fields and rows are called records.

Meta Data:- A description of the structure of the database is known as meta data. it basically means “data about data”.

Application Meta Data:- It stores the structure and format of queries, reports and other application components.

HARDWARE:- In order to run the DBMS and applications, hardware is required. The

hardware consist of the secondary storage device such as magnetic disks and optical disks on which data is stored together..In addition , it includes the I/O devices, processor and maim memory etc. which are used for storing & retrieving the data in fast & efficient manner. Proper care should be taken for choosing the appropriate hardware for a required database.

SOFTWARE:- The software part consist of DBMS which act as a bridge between the user

& the database. In addition to DBMS SOFTWARE, it also includes the application programs, the operating system..Using these software, the users interact with the database.

USER:- User are those person who need information from the database to carry out

their primary business responsibilities i.e. Personnel, staff clerks, Managers, Executives etc. On the basis of the job and requirements made by them, they provided access to the database totally or partially.

The various type of users which can access the database are

Database Administrator(DBA) Database Designer End Users

Casual End Users

Naïve End Users

Standalone End Users Application Programmers

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Shift from computation to information◦ always true for corporate computing◦ Web made this point for personal computing◦ more and more true for scientific computing

Need for DBMS has exploded in the last years◦ Corporate: “customer relationship mgmt”, “supply chain mgmt”,

“data warehouses”, etc.◦ Scientific: digital libraries, Human Genome project, NASA Mission

to Planet Earth, physical sensors, grid physics network DBMS encompasses much of CS in a practical discipline

◦ OS, languages, theory, AI, multimedia, logic◦ Yet traditional focus on real-world apps

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DBMS is the collection of programs which act as an intermediates between the user and the database

DBMS is the software that interprets and processes user’s request to retrieve information from a database

DBMS provides security facilities in a variety of forms, both to prevent unauthorized access and to prevent authorized users from accessing data concurrently without any inconsistency in the database

The primary purpose of a DBMS which is basically a collection of programs is to allow a user to store, update, retrieve data.

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Data Definition

DBMS must be able to access data definition in source form and convert them to the appropriate object form. In other words DBMS must include language processor component for each of the various data definition language(DDL).

Data Manipulation

DBMS must include a DML processor component. The DBMS must be able to handle request from the user to see, retrieve, update , delete or add the new record to the database.

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DATA SECURITY AND INTEGRITY

DBMS must monitor user request & reject any attempt to violate the security & integrity rules define by the DBA.

DATA DICTIONARY

The dictionary contains data about the data rather than the raw data.

Data Dictionary contains the information about entities, attributes, mapping etc.

DBMS should perform all the functions as efficiently as possible.

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A typical DBMS has a layered architecture.

The figure does not show the concurrency control and recovery components.

Each database system has its own variations.

Query Optimization

and ExecutionRelational Operators

Files and Access Methods

Buffer Management

Disk Space Management

DB

These layersmust considerconcurrencycontrol andrecovery

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