data base management system. data data can be a facts related to any object in consideration eg:...

Data Base Management System


• Data• Data can be a facts related to any object in

consideration • Eg: • Name, Age, Height,.. are related to human• Student, Faculty, Classroom… are related to

college


• Data Base• Data base is a systematic collection of data.• Since data in the database is organized, it makes

the data management easy.• Eg:• For a college database might contains

information about the following data• Rollno, Student, Branch,..• The relation ship between data such as student

rollno in which branch etc.


• Data Base Management System (DBMS)• DBMS is a collection of programs which enables its

users to access database, manipulate data, and help in representation of data.

• It also helps to control access to various users• DBMS is a collection of software designed to assist

in maintaining and utilizing large collections of data.• The alternative to using a DBMS is to store the data

in files and write application-specific code to manage it.


• Data Base Management System (DBMS)• Eg:• Online telephone directory use DBMS to store

phone no, name and other details• Electricity service provider use a DBMS to

manage billing, client related issues, etc.• Facebook- uses a DBMS to store, manipulate and

present data, message….


• History• DBMS first implemented in 1960 by Charles

Bachman• Called the Integrated Data Store(IDS).• It is the basis for the network data model• In the late 1960s, IBM developed the

Information Management System (IMS) used even today in many major installations.

• It formed the basis for the hierarchical data model.


• History• In 1970, Edgar Codd, proposed a new data

representation framework called the relational data model.

• In the 1980s, The SQL query language for relational databases, developed as part of IBM's System

• SQL was standardized in the late 1980s. • Current standard, SQL:1999, was adopted by the

American National Standards Institute (ANSI) and International Organization for Standardization (ISO).


• History• In the late 1980s and the 1990s Several vendors

(e.g., IBM‘sDB2, Oracle 8, Informix2 UDS) developed their systems with the ability to store new data types such as images and text, and to ask more complex queries.

• Now DBMS are very familiar in web base system


• Types of DBMS

• Hierarchical DBMS

• Network DBMS

• Relational DBMS

• Object oriented relational DBMS


• Types of DBMS• Hierarchical DBMS• Employs the child relation ship for storing data • like a tree structure • Eg: windows registry in XP • Network DBMS• Support many to many relationships • Represents complex database structures • Eg: RDM server


• Types of DBMS• Relational DBMS• Defines database relationships with relations• Does not support many to many relationships• Have pre defined data types • Eg: MYSql, Oracle, MS-SQL server• Object oriented relational DBMS • Data are stored in the form of objects • Objects are store in the form of attributes • Eg: postgres SQL


• File System Versus DBMS

• Concurrent access Anomalies• Data redundancy• Difficulty in accessing data• Data isolation • Atomicity Problem• Security Problem

Data Base Management System• File System Versus DBMS• Concurrent access Anomalies• File system will not allow to access the same data by

multiple users at same time- it leads to inconsistent (not correct) of data

• Data redundancy (repetition of data)• Data is repeated in file system it needs more storage • For different data, the application program may be

changed – it need more storage• Difficulty in accessing data• No efficient way to access data. Write more lines of code

for retrieving data from file system

Data Base Management System• File System Versus DBMS• Data isolation • Difficulty in retrieving appropriate data• Data may be in different format• Go through the application program and change the

code for retrieving different data in file system• Atomicity Problem• File system cannot restored to a consistent stage after

a failure or crash• Security Problem• User can access any part of the file system


• Advantages of DBMS

• Data Integrity• Roll Back• Security• Concurrency Control• Backup• Data Independence


• Advantages of DBMS• Data Integrity (Accuracy or correctness of Data)• DBMS can enforce integrity constraints. • For example, before inserting information DBMS

can check the data.• Roll Back• Undo an executed statement • Security• No unauthorized user access• it can enforce access controls


• Advantages of DBMS• Concurrency Control• Multiple user access can access of change same

data at same time• Backup• Copies for security, can take copy of data• Data Independence• The DBMS provides an abstract view of the data

that hides some details which are related with.

Data Base Management System• Describing And Storing Data In A DBMS • DBMS is concerned with some real-world enterprise• For example, there are students, faculty, and courses in a

university, are the data in a university database describes these entities and their relationships.

• A data model is a collection of high-level data description constructs that hide many low-level storage details.

• A DBMS allows a user to define the data to be stored in terms of a data model.

• Most DBMS today are based on the relational data model


• Describing And Storing Data In A DBMS • A semantic data model is a more abstract,

makes it easier for a user.

• A widely used semantic data model called the entity-relationship (ER) model


• Describing And Storing Data In A DBMS • The Relational Model• A description of data in terms of a data model is

called a schema.• In the relational model, the schema for a relation

specifies its name, the name of each field (or attribute or column), and the type of each field.

• As an example, student information in a university database may be stored in a relation with the following schema:

• Students( sid: string, name: string, login: string, age: integer)


• Describing And Storing Data In A DBMS • The Relational Model• Students( sid: string, name: string, login: string, age: integer)

• The preceding schema says that each record in the Students relation has 4 fields, with field names and types as indicated.

Sid name login age100 ajith popo 25101 sajith pp 23102 raji raji 25103 kukku koo 34104 appu appus 34

data base management system. data data can be a facts related to any object in consideration eg:...

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