Database Management System
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DATABASE MANAGEMENT SYSTEM
Dharmendra Arora
Recap Database HR File
Fields
Sales File
Payroll File
Record
Record
Record
2511700
DArora
200/day
11001101 1 JIM Arora
11000100 1
0
Dharmendra
0
Bytes
11011100 0
1
0
0
Bits
Traditional File System
Each information need facilitated by specific application associated to a specific master file Which resulted in:
Data Redundancy-same info in more than one files Lack Of Data Integration-collation of information from more than one files not possible Program/Data Dependence-adding data field required change in program, data management scattered among application programs Lack of Flexibility-scheduled reports & queries to retrieve data
Dharmendra Arora
What is Database?
Physical collection of data (Must be stored on direct access devices)
Dharmendra Arora
Why Database
Avoid redundancy Remove Inconsistency Sharing & Synchronization of data Security Data independence Etc.
Dharmendra Arora
Database Management System
Centralised data management software Mechanism for organising, structuring & storing data Set of programs that serve an interface between application programs and database (set of coordinated and integrated physical files) DBMS provides capabilities of creating, maintaining and changing the database Dharmendra
Arora
Dharmendra Arora
India
Rajasthan
Dharmendra Arora
Freelance Consultant
8 Years
Dharmendra Arora
ICICI Bank
0001122333
Personal
211111 talkSmart 25000
DBMS
Professional Financial
Query Language Users
Dharmendra Arora
Database
Reports
Who Are The Users?
End User-Logical view Application Programmer-Logical/Physical view Database Administrator-for overall control of Db.
Data dictionary Physical structure Updation of database Security & recovery Access control Etc. Dharmendra
Arora
Logical & Physical Views
Physical view-physical layout of the database records; actual records of bits, bytes on memory devices. Used by technical people to optimise memory devise for space and performance. Logical view- data represented in userdesired format.
Dharmendra Arora
Elements of DBMS 1. 2. 3.
Data Definition Language (DDL Data Manipulation Language (DML) Utilities & Ancillary Software
Dharmendra Arora
Data Definition Language (DDL)
Means by which the content & format of data to be stored is described; and the structure of db is defined. It is essentially a link between Logical view and physical views of database.
Dharmendra Arora
JIM Arora
Dharmendra
JIM Arora
Dharmendra
Data Manipulation Language (DML)
Set of procedural commands that allow the user to store, retrieve and amend the database. Eg. Select * from personal_info;
Dharmendra Arora
Utilities & Ancillary Software
Physical administration of database Wizards for reports etc.
Dharmendra Arora
Database Models
It defines the way/fashion in which the data is structured/coordinated-the way related data is tied together. 3 major models 1. 2. 3.
Relational Database-based on relational theory Hierarchical Database-based on graph theory Network Database-based on graph theory
Dharmendra Arora
Relational Database
Introduced by Codd in early 1970s Composed of one or more relations. Each can be visualised as a table of data or file. Each row (tuple) in the relation represents one entity. Each column name represents attribute. The value of an attribute is called an item. In any relation no two rows can be identical. An attribute or set of attributes whose value uniquely identify a row of a relation is called a key. Dharmendra
Arora
Example of Relational Db Course # Title course
Course #Contents contents
Course # Pre# Prereq
Course # Emp# teacher
Course # Roll# Roll # StuName Dharmendra Arora
Grade
Course students
students
Hierarchical Database
Data represented by tree-structure type of organisation. The hierarchical tree specifies what record types are allowed to be included in the database and the permissible relations between record types. Any record other than the root or the tree must be connected with a parent record. When a record is deleted, all the descendants of the records are also deleted. Dharmendra
Arora
Example of Hierarchical Db Course #
contents Contents
course
Title
Pre#
Roll#
Prereq
Grade
StuName Dharmendra Arora
Emp# teacher Course students
students
Network Database
Generalisation of hierarchical model. In this a segment can have multiple parent segments. Many-to-many structure rather than oneto-many.
Dharmendra Arora
Example of Hierarchical Db Course # hascon
contents Contents
course
Title
hastea
corpre
Pre#
Prereq
fulfil
Roll#
Grade
attends
Dharmendra Arora
Emp# teacher Course students takestest
StuName students
Which model to use
Ease of use-relational Efficiency of implementation-others
Dharmendra Arora
Dharmendra Arora
Recap Database HR File
Fields
Sales File
Payroll File
Record
Record
Record
2511700
DArora
200/day
11001101 1 JIM Arora
11000100 1
0
Dharmendra
0
Bytes
11011100 0
1
0
0
Bits
Traditional File System
Each information need facilitated by specific application associated to a specific master file Which resulted in:
Data Redundancy-same info in more than one files Lack Of Data Integration-collation of information from more than one files not possible Program/Data Dependence-adding data field required change in program, data management scattered among application programs Lack of Flexibility-scheduled reports & queries to retrieve data
Dharmendra Arora
What is Database?
Physical collection of data (Must be stored on direct access devices)
Dharmendra Arora
Why Database
Avoid redundancy Remove Inconsistency Sharing & Synchronization of data Security Data independence Etc.
Dharmendra Arora
Database Management System
Centralised data management software Mechanism for organising, structuring & storing data Set of programs that serve an interface between application programs and database (set of coordinated and integrated physical files) DBMS provides capabilities of creating, maintaining and changing the database Dharmendra
Arora
Dharmendra Arora
India
Rajasthan
Dharmendra Arora
Freelance Consultant
8 Years
Dharmendra Arora
ICICI Bank
0001122333
Personal
211111 talkSmart 25000
DBMS
Professional Financial
Query Language Users
Dharmendra Arora
Database
Reports
Who Are The Users?
End User-Logical view Application Programmer-Logical/Physical view Database Administrator-for overall control of Db.
Data dictionary Physical structure Updation of database Security & recovery Access control Etc. Dharmendra
Arora
Logical & Physical Views
Physical view-physical layout of the database records; actual records of bits, bytes on memory devices. Used by technical people to optimise memory devise for space and performance. Logical view- data represented in userdesired format.
Dharmendra Arora
Elements of DBMS 1. 2. 3.
Data Definition Language (DDL Data Manipulation Language (DML) Utilities & Ancillary Software
Dharmendra Arora
Data Definition Language (DDL)
Means by which the content & format of data to be stored is described; and the structure of db is defined. It is essentially a link between Logical view and physical views of database.
Dharmendra Arora
JIM Arora
Dharmendra
JIM Arora
Dharmendra
Data Manipulation Language (DML)
Set of procedural commands that allow the user to store, retrieve and amend the database. Eg. Select * from personal_info;
Dharmendra Arora
Utilities & Ancillary Software
Physical administration of database Wizards for reports etc.
Dharmendra Arora
Database Models
It defines the way/fashion in which the data is structured/coordinated-the way related data is tied together. 3 major models 1. 2. 3.
Relational Database-based on relational theory Hierarchical Database-based on graph theory Network Database-based on graph theory
Dharmendra Arora
Relational Database
Introduced by Codd in early 1970s Composed of one or more relations. Each can be visualised as a table of data or file. Each row (tuple) in the relation represents one entity. Each column name represents attribute. The value of an attribute is called an item. In any relation no two rows can be identical. An attribute or set of attributes whose value uniquely identify a row of a relation is called a key. Dharmendra
Arora
Example of Relational Db Course # Title course
Course #Contents contents
Course # Pre# Prereq
Course # Emp# teacher
Course # Roll# Roll # StuName Dharmendra Arora
Grade
Course students
students
Hierarchical Database
Data represented by tree-structure type of organisation. The hierarchical tree specifies what record types are allowed to be included in the database and the permissible relations between record types. Any record other than the root or the tree must be connected with a parent record. When a record is deleted, all the descendants of the records are also deleted. Dharmendra
Arora
Example of Hierarchical Db Course #
contents Contents
course
Title
Pre#
Roll#
Prereq
Grade
StuName Dharmendra Arora
Emp# teacher Course students
students
Network Database
Generalisation of hierarchical model. In this a segment can have multiple parent segments. Many-to-many structure rather than oneto-many.
Dharmendra Arora
Example of Hierarchical Db Course # hascon
contents Contents
course
Title
hastea
corpre
Pre#
Prereq
fulfil
Roll#
Grade
attends
Dharmendra Arora
Emp# teacher Course students takestest
StuName students
Which model to use
Ease of use-relational Efficiency of implementation-others
Dharmendra Arora
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