SlideShare a Scribd company logo

Ch01

DBMS

1 of 29
Download to read offline
Chapter 1: Introduction
Database Management System
(DBMS)
• DBMS contains information about a particular enterprise
– Collection of interrelated data
– Set of programs to access the data
– An environment that is both convenient and efficient to use
• Database Applications:
– Banking: transactions
– Airlines: reservations, schedules
– Universities: registration, grades
– Sales: customers, products, purchases
– Online retailers: order tracking, customized recommendations
– Manufacturing: production, inventory, orders, supply chain
– Human resources: employee records, salaries, tax deductions
• Databases can be very large.
• Databases touch all aspects of our lives
University Database Example
• Application program examples
– Add new students, instructors, and courses
– Register students for courses, and generate
class rosters
– Assign grades to students, compute grade point
averages (GPA) and generate transcripts
• In the early days, database applications
were built directly on top of file systems
Characteristics of DBMS
1.Data Integrity
This is one of the most important characteristics of database management system. Integrity ensures the
quality and reliability of database system. It protects unauthorized access of database and makes it more
secure. It brings only consistence and accurate data into the database.
2.Security
DBMS provides security to the data stored in it because all users have different rights to access
database. Some of the user can access the whole database while other can access a small part of
database. For example, a computer network lecturer can only access files that are related to
computer subjects but HOD of the department can access files of all subject that are related to
their department.
3.Transactions control/Rollback
Transactions are bunch of actions that are done to bring database from one consistent state to new
consistent state. Traditional file-based system did not have this feature. Transaction is always
atomic that means it can never be further divided. It can only be completed or uncompleted.
For example, A person wants to credit money from his account to another person’s account. Then
transaction will be complete if he sends money and other guy receives his money. Anything other
than this can lead to an inconsistent transaction.
4.Concurrent Use of Database
There are many chances that many users will be accessing the data at the same time. They
may require altering the database system concurrently. At that time, DBMS supports them
to concurrently use database without any problem. With the help of concurrency, economy
of the system can be increased. For Example, employees of railway reservation system can
book and access tickets for passengers concurrently. Every employee can see on his own
interface that how many seats are available or bogie is fully booked.
5.Data independence
Program-data independence provides a big relief to database users. In traditional file
management system, structure of data files was defined in the application programs so user
had to change all the programs that are using that particular data file.
6.Backup and Recovery
There are many chances of failure of whole database. At that time no one will be able to get
the database back and for sure company will be in a big loss. The only solution is to take
backup of database and whenever it is needed, it can be stored back. A database must have
this characteristic to enable more effectiveness
1. File System :
File system is basically a way of arranging the files in a storage medium
like hard disk. File system organizes the files and helps in retrieval of files when
they are required. File systems consists of different files which are grouped into
directories. The directories further contain other folders and files. File system
performs basic operations like management, file naming, giving access rules etc.
2.DBMS(Database Management System) :
Database Management System is basically a software that manages
the collection of related data. It is used for storing data and retrieving the data
effectively when it is needed. It also provides proper security measures for protecting
the data from unauthorized access. In Database Management System the data can be
fetched by SQL queries and relational algebra. It also provides mechanisms for data
recovery and data backup.
FILE SYSTEM V/S DATABASE SYSTEM

Recommended

More Related Content

What's hot

Database Presentation
Database PresentationDatabase Presentation
Database Presentationa9oolq8
 
Beginning Of DBMS (data base)
Beginning Of DBMS (data base)Beginning Of DBMS (data base)
Beginning Of DBMS (data base)Surya Swaroop
 
Database Management Systems - Management Information System
Database Management Systems - Management Information SystemDatabase Management Systems - Management Information System
Database Management Systems - Management Information SystemNijaz N
 
Mca ii-dbms- u-i-introductory concepts of dbms
Mca ii-dbms- u-i-introductory concepts of dbmsMca ii-dbms- u-i-introductory concepts of dbms
Mca ii-dbms- u-i-introductory concepts of dbmsRai University
 
Pmit 6102-14-lec1-intro
Pmit 6102-14-lec1-introPmit 6102-14-lec1-intro
Pmit 6102-14-lec1-introJesmin Rahaman
 
introduction to database
 introduction to database introduction to database
introduction to databaseAkif shexi
 
Introduction & history of dbms
Introduction & history of dbmsIntroduction & history of dbms
Introduction & history of dbmssethu pm
 
Chapter 01 Fundamental of Database Management System (DBMS)
Chapter 01  Fundamental of Database Management System (DBMS)Chapter 01  Fundamental of Database Management System (DBMS)
Chapter 01 Fundamental of Database Management System (DBMS)Abdurehman Mahmud
 
Data base management system
Data base management systemData base management system
Data base management systemNavneet Jingar
 
File system-and-database-chapter01-connoly
File system-and-database-chapter01-connolyFile system-and-database-chapter01-connoly
File system-and-database-chapter01-connolyTemma Tems
 
Introduction of dbms
Introduction of dbmsIntroduction of dbms
Introduction of dbmsRUpaliLohar
 
Presentation on Database management system
Presentation on Database management systemPresentation on Database management system
Presentation on Database management systemPrerana Bhattarai
 
Bsc cs ii-dbms- u-i-database systems
Bsc cs ii-dbms- u-i-database systemsBsc cs ii-dbms- u-i-database systems
Bsc cs ii-dbms- u-i-database systemsRai University
 

What's hot (20)

Dbms notes
Dbms notesDbms notes
Dbms notes
 
Unit1 DBMS Introduction
Unit1 DBMS IntroductionUnit1 DBMS Introduction
Unit1 DBMS Introduction
 
Over View of DBMS
Over View of DBMS Over View of DBMS
Over View of DBMS
 
DBMS 1 | Introduction to DBMS
DBMS 1 | Introduction to DBMSDBMS 1 | Introduction to DBMS
DBMS 1 | Introduction to DBMS
 
Database Presentation
Database PresentationDatabase Presentation
Database Presentation
 
Unit 01 dbms
Unit 01 dbmsUnit 01 dbms
Unit 01 dbms
 
Beginning Of DBMS (data base)
Beginning Of DBMS (data base)Beginning Of DBMS (data base)
Beginning Of DBMS (data base)
 
Database Management Systems - Management Information System
Database Management Systems - Management Information SystemDatabase Management Systems - Management Information System
Database Management Systems - Management Information System
 
Mca ii-dbms- u-i-introductory concepts of dbms
Mca ii-dbms- u-i-introductory concepts of dbmsMca ii-dbms- u-i-introductory concepts of dbms
Mca ii-dbms- u-i-introductory concepts of dbms
 
Pmit 6102-14-lec1-intro
Pmit 6102-14-lec1-introPmit 6102-14-lec1-intro
Pmit 6102-14-lec1-intro
 
introduction to database
 introduction to database introduction to database
introduction to database
 
Introduction & history of dbms
Introduction & history of dbmsIntroduction & history of dbms
Introduction & history of dbms
 
DBMS
DBMSDBMS
DBMS
 
Chapter 01 Fundamental of Database Management System (DBMS)
Chapter 01  Fundamental of Database Management System (DBMS)Chapter 01  Fundamental of Database Management System (DBMS)
Chapter 01 Fundamental of Database Management System (DBMS)
 
Data base management system
Data base management systemData base management system
Data base management system
 
File system-and-database-chapter01-connoly
File system-and-database-chapter01-connolyFile system-and-database-chapter01-connoly
File system-and-database-chapter01-connoly
 
Introduction of dbms
Introduction of dbmsIntroduction of dbms
Introduction of dbms
 
DBMS - Introduction
DBMS - IntroductionDBMS - Introduction
DBMS - Introduction
 
Presentation on Database management system
Presentation on Database management systemPresentation on Database management system
Presentation on Database management system
 
Bsc cs ii-dbms- u-i-database systems
Bsc cs ii-dbms- u-i-database systemsBsc cs ii-dbms- u-i-database systems
Bsc cs ii-dbms- u-i-database systems
 

Similar to Ch01

Similar to Ch01 (20)

Dbms mca-section a
Dbms mca-section aDbms mca-section a
Dbms mca-section a
 
Unit 1.pptx
Unit 1.pptxUnit 1.pptx
Unit 1.pptx
 
Unit1 dbms
Unit1 dbmsUnit1 dbms
Unit1 dbms
 
Dbms
DbmsDbms
Dbms
 
Database, Lecture-1.ppt
Database, Lecture-1.pptDatabase, Lecture-1.ppt
Database, Lecture-1.ppt
 
Intro.pptx
Intro.pptxIntro.pptx
Intro.pptx
 
Unit 1: Introduction to DBMS Unit 1 Complete
Unit 1: Introduction to DBMS Unit 1 CompleteUnit 1: Introduction to DBMS Unit 1 Complete
Unit 1: Introduction to DBMS Unit 1 Complete
 
Lecture 1 =Unit 1 Part 1.ppt
Lecture 1 =Unit 1 Part 1.pptLecture 1 =Unit 1 Part 1.ppt
Lecture 1 =Unit 1 Part 1.ppt
 
8.DBMS.pptx
8.DBMS.pptx8.DBMS.pptx
8.DBMS.pptx
 
DBMS-1.pptx
DBMS-1.pptxDBMS-1.pptx
DBMS-1.pptx
 
DBMS-Unit-1.pptx
DBMS-Unit-1.pptxDBMS-Unit-1.pptx
DBMS-Unit-1.pptx
 
Introduction to DBMS_VP.pptx
Introduction to DBMS_VP.pptxIntroduction to DBMS_VP.pptx
Introduction to DBMS_VP.pptx
 
Database
DatabaseDatabase
Database
 
Dbms Useful PPT
Dbms Useful PPTDbms Useful PPT
Dbms Useful PPT
 
Database Management System.pptx
Database Management System.pptxDatabase Management System.pptx
Database Management System.pptx
 
Database & dbms
Database & dbmsDatabase & dbms
Database & dbms
 
Unit 2 rdbms study_material
Unit 2  rdbms study_materialUnit 2  rdbms study_material
Unit 2 rdbms study_material
 
Introduction To Database.ppt
Introduction To Database.pptIntroduction To Database.ppt
Introduction To Database.ppt
 
Database management systems
Database management systemsDatabase management systems
Database management systems
 
Database and Database Management (DBM): Health Informatics
Database and Database Management (DBM): Health InformaticsDatabase and Database Management (DBM): Health Informatics
Database and Database Management (DBM): Health Informatics
 

Recently uploaded

TrustArc Webinar - TrustArc's Latest AI Innovations
TrustArc Webinar - TrustArc's Latest AI InnovationsTrustArc Webinar - TrustArc's Latest AI Innovations
TrustArc Webinar - TrustArc's Latest AI InnovationsTrustArc
 
AMER Introduction to ThousandEyes Webinar
AMER Introduction to ThousandEyes WebinarAMER Introduction to ThousandEyes Webinar
AMER Introduction to ThousandEyes WebinarThousandEyes
 
Establishing data sharing standards to promote global industry development
Establishing data sharing standards to promote global industry developmentEstablishing data sharing standards to promote global industry development
Establishing data sharing standards to promote global industry developmentThorsten Huelsmann
 
Key projects in AI, ML and Generative AI
Key projects in AI, ML and Generative AIKey projects in AI, ML and Generative AI
Key projects in AI, ML and Generative AIVijayananda Mohire
 
AI improves software testing to be more fault tolerant, focused and efficient
AI improves software testing to be more fault tolerant, focused and efficientAI improves software testing to be more fault tolerant, focused and efficient
AI improves software testing to be more fault tolerant, focused and efficientKari Kakkonen
 
Unleash the Solace Pub Sub connector | Banaglore MuleSoft Meetup #31
Unleash the Solace Pub Sub connector | Banaglore MuleSoft Meetup #31Unleash the Solace Pub Sub connector | Banaglore MuleSoft Meetup #31
Unleash the Solace Pub Sub connector | Banaglore MuleSoft Meetup #31shyamraj55
 
Low Latency at Extreme Scale: Proven Practices & Pitfalls
Low Latency at Extreme Scale: Proven Practices & PitfallsLow Latency at Extreme Scale: Proven Practices & Pitfalls
Low Latency at Extreme Scale: Proven Practices & PitfallsScyllaDB
 
Transcript: Trending now: Book subjects on the move in the Canadian market - ...
Transcript: Trending now: Book subjects on the move in the Canadian market - ...Transcript: Trending now: Book subjects on the move in the Canadian market - ...
Transcript: Trending now: Book subjects on the move in the Canadian market - ...BookNet Canada
 
Building Bridges: Merging RPA Processes, UiPath Apps, and Data Service to bu...
Building Bridges:  Merging RPA Processes, UiPath Apps, and Data Service to bu...Building Bridges:  Merging RPA Processes, UiPath Apps, and Data Service to bu...
Building Bridges: Merging RPA Processes, UiPath Apps, and Data Service to bu...DianaGray10
 
ChatGPT's Code Interpreter: Your secret weapon for SEO automation success - S...
ChatGPT's Code Interpreter: Your secret weapon for SEO automation success - S...ChatGPT's Code Interpreter: Your secret weapon for SEO automation success - S...
ChatGPT's Code Interpreter: Your secret weapon for SEO automation success - S...SearchNorwich
 
What’s New in CloudStack 4.19, Abhishek Kumar, Release Manager Apache CloudSt...
What’s New in CloudStack 4.19, Abhishek Kumar, Release Manager Apache CloudSt...What’s New in CloudStack 4.19, Abhishek Kumar, Release Manager Apache CloudSt...
What’s New in CloudStack 4.19, Abhishek Kumar, Release Manager Apache CloudSt...ShapeBlue
 
Large Language Models and Applications in Healthcare
Large Language Models and Applications in HealthcareLarge Language Models and Applications in Healthcare
Large Language Models and Applications in HealthcareAsma Ben Abacha
 
Pragmatic UI testing with Compose Semantics.pdf
Pragmatic UI testing with Compose Semantics.pdfPragmatic UI testing with Compose Semantics.pdf
Pragmatic UI testing with Compose Semantics.pdfinfogdgmi
 
CloudStack Authentication Methods – Harikrishna Patnala, ShapeBlue
CloudStack Authentication Methods – Harikrishna Patnala, ShapeBlueCloudStack Authentication Methods – Harikrishna Patnala, ShapeBlue
CloudStack Authentication Methods – Harikrishna Patnala, ShapeBlueShapeBlue
 
AGFM - Toyota Coaster 1HZ Install Guide.pdf
AGFM - Toyota Coaster 1HZ Install Guide.pdfAGFM - Toyota Coaster 1HZ Install Guide.pdf
AGFM - Toyota Coaster 1HZ Install Guide.pdfRodneyThomas28
 
GDG Cloud Southlake 30 Brian Demers Breeding 10x Developers with Developer Pr...
GDG Cloud Southlake 30 Brian Demers Breeding 10x Developers with Developer Pr...GDG Cloud Southlake 30 Brian Demers Breeding 10x Developers with Developer Pr...
GDG Cloud Southlake 30 Brian Demers Breeding 10x Developers with Developer Pr...James Anderson
 
Q4 2023 Quarterly Investor Presentation - FINAL.pdf
Q4 2023 Quarterly Investor Presentation - FINAL.pdfQ4 2023 Quarterly Investor Presentation - FINAL.pdf
Q4 2023 Quarterly Investor Presentation - FINAL.pdfTejal81
 
CloudStack Tooling Ecosystem – Kiran Chavala, ShapeBlue
CloudStack Tooling Ecosystem – Kiran Chavala, ShapeBlueCloudStack Tooling Ecosystem – Kiran Chavala, ShapeBlue
CloudStack Tooling Ecosystem – Kiran Chavala, ShapeBlueShapeBlue
 
Improving IT Investment Decisions and Business Outcomes with Integrated Enter...
Improving IT Investment Decisions and Business Outcomes with Integrated Enter...Improving IT Investment Decisions and Business Outcomes with Integrated Enter...
Improving IT Investment Decisions and Business Outcomes with Integrated Enter...Cprime
 
Roundtable_-_API_Research__Testing_Tools.pdf
Roundtable_-_API_Research__Testing_Tools.pdfRoundtable_-_API_Research__Testing_Tools.pdf
Roundtable_-_API_Research__Testing_Tools.pdfMostafa Higazy
 

Recently uploaded (20)

TrustArc Webinar - TrustArc's Latest AI Innovations
TrustArc Webinar - TrustArc's Latest AI InnovationsTrustArc Webinar - TrustArc's Latest AI Innovations
TrustArc Webinar - TrustArc's Latest AI Innovations
 
AMER Introduction to ThousandEyes Webinar
AMER Introduction to ThousandEyes WebinarAMER Introduction to ThousandEyes Webinar
AMER Introduction to ThousandEyes Webinar
 
Establishing data sharing standards to promote global industry development
Establishing data sharing standards to promote global industry developmentEstablishing data sharing standards to promote global industry development
Establishing data sharing standards to promote global industry development
 
Key projects in AI, ML and Generative AI
Key projects in AI, ML and Generative AIKey projects in AI, ML and Generative AI
Key projects in AI, ML and Generative AI
 
AI improves software testing to be more fault tolerant, focused and efficient
AI improves software testing to be more fault tolerant, focused and efficientAI improves software testing to be more fault tolerant, focused and efficient
AI improves software testing to be more fault tolerant, focused and efficient
 
Unleash the Solace Pub Sub connector | Banaglore MuleSoft Meetup #31
Unleash the Solace Pub Sub connector | Banaglore MuleSoft Meetup #31Unleash the Solace Pub Sub connector | Banaglore MuleSoft Meetup #31
Unleash the Solace Pub Sub connector | Banaglore MuleSoft Meetup #31
 
Low Latency at Extreme Scale: Proven Practices & Pitfalls
Low Latency at Extreme Scale: Proven Practices & PitfallsLow Latency at Extreme Scale: Proven Practices & Pitfalls
Low Latency at Extreme Scale: Proven Practices & Pitfalls
 
Transcript: Trending now: Book subjects on the move in the Canadian market - ...
Transcript: Trending now: Book subjects on the move in the Canadian market - ...Transcript: Trending now: Book subjects on the move in the Canadian market - ...
Transcript: Trending now: Book subjects on the move in the Canadian market - ...
 
Building Bridges: Merging RPA Processes, UiPath Apps, and Data Service to bu...
Building Bridges:  Merging RPA Processes, UiPath Apps, and Data Service to bu...Building Bridges:  Merging RPA Processes, UiPath Apps, and Data Service to bu...
Building Bridges: Merging RPA Processes, UiPath Apps, and Data Service to bu...
 
ChatGPT's Code Interpreter: Your secret weapon for SEO automation success - S...
ChatGPT's Code Interpreter: Your secret weapon for SEO automation success - S...ChatGPT's Code Interpreter: Your secret weapon for SEO automation success - S...
ChatGPT's Code Interpreter: Your secret weapon for SEO automation success - S...
 
What’s New in CloudStack 4.19, Abhishek Kumar, Release Manager Apache CloudSt...
What’s New in CloudStack 4.19, Abhishek Kumar, Release Manager Apache CloudSt...What’s New in CloudStack 4.19, Abhishek Kumar, Release Manager Apache CloudSt...
What’s New in CloudStack 4.19, Abhishek Kumar, Release Manager Apache CloudSt...
 
Large Language Models and Applications in Healthcare
Large Language Models and Applications in HealthcareLarge Language Models and Applications in Healthcare
Large Language Models and Applications in Healthcare
 
Pragmatic UI testing with Compose Semantics.pdf
Pragmatic UI testing with Compose Semantics.pdfPragmatic UI testing with Compose Semantics.pdf
Pragmatic UI testing with Compose Semantics.pdf
 
CloudStack Authentication Methods – Harikrishna Patnala, ShapeBlue
CloudStack Authentication Methods – Harikrishna Patnala, ShapeBlueCloudStack Authentication Methods – Harikrishna Patnala, ShapeBlue
CloudStack Authentication Methods – Harikrishna Patnala, ShapeBlue
 
AGFM - Toyota Coaster 1HZ Install Guide.pdf
AGFM - Toyota Coaster 1HZ Install Guide.pdfAGFM - Toyota Coaster 1HZ Install Guide.pdf
AGFM - Toyota Coaster 1HZ Install Guide.pdf
 
GDG Cloud Southlake 30 Brian Demers Breeding 10x Developers with Developer Pr...
GDG Cloud Southlake 30 Brian Demers Breeding 10x Developers with Developer Pr...GDG Cloud Southlake 30 Brian Demers Breeding 10x Developers with Developer Pr...
GDG Cloud Southlake 30 Brian Demers Breeding 10x Developers with Developer Pr...
 
Q4 2023 Quarterly Investor Presentation - FINAL.pdf
Q4 2023 Quarterly Investor Presentation - FINAL.pdfQ4 2023 Quarterly Investor Presentation - FINAL.pdf
Q4 2023 Quarterly Investor Presentation - FINAL.pdf
 
CloudStack Tooling Ecosystem – Kiran Chavala, ShapeBlue
CloudStack Tooling Ecosystem – Kiran Chavala, ShapeBlueCloudStack Tooling Ecosystem – Kiran Chavala, ShapeBlue
CloudStack Tooling Ecosystem – Kiran Chavala, ShapeBlue
 
Improving IT Investment Decisions and Business Outcomes with Integrated Enter...
Improving IT Investment Decisions and Business Outcomes with Integrated Enter...Improving IT Investment Decisions and Business Outcomes with Integrated Enter...
Improving IT Investment Decisions and Business Outcomes with Integrated Enter...
 
Roundtable_-_API_Research__Testing_Tools.pdf
Roundtable_-_API_Research__Testing_Tools.pdfRoundtable_-_API_Research__Testing_Tools.pdf
Roundtable_-_API_Research__Testing_Tools.pdf
 

Ch01

  • 2. Database Management System (DBMS) • DBMS contains information about a particular enterprise – Collection of interrelated data – Set of programs to access the data – An environment that is both convenient and efficient to use • Database Applications: – Banking: transactions – Airlines: reservations, schedules – Universities: registration, grades – Sales: customers, products, purchases – Online retailers: order tracking, customized recommendations – Manufacturing: production, inventory, orders, supply chain – Human resources: employee records, salaries, tax deductions • Databases can be very large. • Databases touch all aspects of our lives
  • 3. University Database Example • Application program examples – Add new students, instructors, and courses – Register students for courses, and generate class rosters – Assign grades to students, compute grade point averages (GPA) and generate transcripts • In the early days, database applications were built directly on top of file systems
  • 4. Characteristics of DBMS 1.Data Integrity This is one of the most important characteristics of database management system. Integrity ensures the quality and reliability of database system. It protects unauthorized access of database and makes it more secure. It brings only consistence and accurate data into the database. 2.Security DBMS provides security to the data stored in it because all users have different rights to access database. Some of the user can access the whole database while other can access a small part of database. For example, a computer network lecturer can only access files that are related to computer subjects but HOD of the department can access files of all subject that are related to their department. 3.Transactions control/Rollback Transactions are bunch of actions that are done to bring database from one consistent state to new consistent state. Traditional file-based system did not have this feature. Transaction is always atomic that means it can never be further divided. It can only be completed or uncompleted. For example, A person wants to credit money from his account to another person’s account. Then transaction will be complete if he sends money and other guy receives his money. Anything other than this can lead to an inconsistent transaction.
  • 5. 4.Concurrent Use of Database There are many chances that many users will be accessing the data at the same time. They may require altering the database system concurrently. At that time, DBMS supports them to concurrently use database without any problem. With the help of concurrency, economy of the system can be increased. For Example, employees of railway reservation system can book and access tickets for passengers concurrently. Every employee can see on his own interface that how many seats are available or bogie is fully booked. 5.Data independence Program-data independence provides a big relief to database users. In traditional file management system, structure of data files was defined in the application programs so user had to change all the programs that are using that particular data file. 6.Backup and Recovery There are many chances of failure of whole database. At that time no one will be able to get the database back and for sure company will be in a big loss. The only solution is to take backup of database and whenever it is needed, it can be stored back. A database must have this characteristic to enable more effectiveness
  • 6. 1. File System : File system is basically a way of arranging the files in a storage medium like hard disk. File system organizes the files and helps in retrieval of files when they are required. File systems consists of different files which are grouped into directories. The directories further contain other folders and files. File system performs basic operations like management, file naming, giving access rules etc. 2.DBMS(Database Management System) : Database Management System is basically a software that manages the collection of related data. It is used for storing data and retrieving the data effectively when it is needed. It also provides proper security measures for protecting the data from unauthorized access. In Database Management System the data can be fetched by SQL queries and relational algebra. It also provides mechanisms for data recovery and data backup. FILE SYSTEM V/S DATABASE SYSTEM
  • 7. FILE SYSTEM DBMS File system is a software that manages ad organizes the files in a storage medium within a computer. DBMS is a software for managing the database. Redundant data can be present in a file system. In DBMS there is no redundant data. It doesn’t provide backup and recovery of data if it is lost. It provides backup and recovery of data even if it is lost. There is no efficient query processing in file system. Efficient query processing is there in DBMS. There is less data consistency in file system. There is more data consistency because of the process of normalization. It is less complex as compared to DBMS. It has more complexity in handling as compared to file system. File systems provide less security in comparison to DBMS. DBMS has more security mechanisms as compared to file system. It is less expensive than DBMS. It has a comparatively higher cost than a file system. Difference between File System and DBMS :
  • 8. Drawbacks of using file systems to store data – Data redundancy and inconsistency • Multiple file formats, duplication of information in different files – Difficulty in accessing data • Need to write a new program to carry out each new task – Data isolation — multiple files and formats – Integrity problems • Integrity constraints (e.g., account balance > 0) Hard to add new constraints or change existing ones
  • 9. Drawbacks of using file systems to store data (Cont.) – Atomicity of updates • Failures may leave database in an inconsistent state with partial updates carried out • Example: Transfer of funds from one account to another should either complete or not happen at all – Concurrent access by multiple users • Concurrent access needed for performance • Uncontrolled concurrent accesses can lead to inconsistencies – Example: Two people reading a balance (say 100) and updating it by withdrawing money (say 50 each) at the same time – Security problems • Hard to provide user access to some, but not all, data Database systems offer solutions to all the above problems
  • 10. Levels of Abstraction • Physical level: describes how a record (e.g., customer) is stored. • Logical level: describes data stored in database, and the relationships among the data. type instructor = record ID : string; name : string; dept_name : string; salary : integer; end; • View level: application programs hide details of data types. Views can also hide information (such as an employee’s salary) for security purposes.
  • 11. View of Data The three levels of data abstraction
  • 12. Instances and Schemas • Similar to types and variables in programming languages • Schema – the logical structure of the database. The overall design of the database is called the database schema. – Example: The database consists of information about a set of customers and accounts and the relationship between them – Analogous to type information of a variable in a program – Physical schema: database design at the physical level – Logical schema: database design at the logical level • Instance – the actual content of the database at a particular point in time • The collection of information stored in the database at a particular moment is called an instance of the database. – Analogous to the value of a variable
  • 13. Data Independence is defined as a property of DBMS that helps you to change the Database schema at one level of a database system without requiring to change the schema at the next higher level. Data independence helps you to keep data separated from all programs that make use of it. Data Independence Types of Data Independence In DBMS there are two types of data independence 1.Physical data independence 2.Logical data independence. Physical Data Independence All the schemas are logical, and the actual data is stored in bit format on the disk. The ability to modify the physical schema without changing the logical schema. –Applications depend on the logical schema Logical Data Independence Logical data is data about database, that is, it stores information about how data is managed inside. For example, a table (relation) stored in the database and all its constraints, applied on that relation. Logical data independence is a kind of mechanism, which liberalizes itself from actual data stored on the disk. If we do some changes on table format, it should not change the data residing on the disk.
  • 14. Data Models • A collection of tools for describing – Data – Data relationships – Data semantics – Data constraints • Relational model • Entity-Relationship data model (mainly for database design) • Object-based data models (Object-oriented and Object-relational) • Semi structured data model (XML) • Other older models: – Network model – Hierarchical model
  • 15. Relational Model • Relational model (Chapter 2) • Example of tabular data in the relational modelColumns Rows
  • 17. Database Design The process of designing the general structure of the database: • Logical Design – Deciding on the database schema. Database design requires that we find a “good” collection of relation schemas. – Business decision – What attributes should we record in the database? – Computer Science decision – What relation schemas should we have and how should the attributes be distributed among the various relation schemas? • Physical Design – Deciding on the physical layout of the database
  • 18. Database Design? • Is there any problem with this design?
  • 19. The Entity-Relationship Model • Models an enterprise as a collection of entities and relationships – Entity: a “thing” or “object” in the enterprise that is distinguishable from other objects • Described by a set of attributes – Relationship: an association among several entities • Represented diagrammatically by an entity-relationship diagram: What happened to dept_name of instructor and student?
  • 20. Object-Relational Data Models • Relational model: flat, “atomic” values • Object Relational Data Models – Extend the relational data model by including object orientation and constructs to deal with added data types. – Allow attributes of tuples to have complex types, including non-atomic values such as nested relations. – Preserve relational foundations, in particular the declarative access to data, while extending modeling power. – Provide upward compatibility with existing relational languages.
  • 22. Database Architecture A database system is partitioned into modules that deal with each of the responsibilities of the overall system. The functional components of a database system can be broadly divided into the storage manager and the query processor components. The storage manager is important because databases typically require a large amount of storage space. Corporate databases range in size from hundreds of gigabytes to, for the largest databases, terabytes of data. A gigabyte is 1000 mega bytes and a terabyte is 1 million megabytes (1 trillion bytes). Since the main memory of computers cannot store this much information, the information is stored on disks. Data are moved between disk storage and main memory as needed. Since the movement of data to and from disk is slow relative to the speed of the central processing unit, it is imperative that the database system.
  • 23. Storage Management • Storage manager is a program module that provides the interface between the low-level data stored in the database and the application programs and queries submitted to the system. • The storage manager is responsible to the following tasks: – Interaction with the file manager – Efficient storing, retrieving and updating of data • Issues: – Storage access – File organization – Indexing and hashing
  • 24. • Authorization and integrity manager, which tests for the satisfaction of integrity constraints and checks the authority of users to access data. • Transaction manager, which ensures that the database remains in a consistent (correct) state despite system failures, and that concurrent transaction executions proceed without conflicting. • File manager, which manages the allocation of space on disk storage and the data structures used to represent information stored on disk. • Buffer manager, which is responsible for fetching data from disk storage into main memory, and deciding what data to cache in main memory. The buffer manager is a critical part of the database system, since it enables the database to handle data sizes that are much larger than the size of main memory. The storage manager implements several data structures as part of the physical system implementation: • Data files, which store the database itself. • Data dictionary, which stores metadata about the structure of the database, in particular the schema of the database. • Indices, which provide fast access to data items that hold particular values. The storage manager components include:
  • 25. Query Processing 1.Parsing and translation 2.Optimization 3.Evaluation
  • 26. Query Processing (Cont.) The query processor components include • DDL interpreter, which interprets DDL statements and records the definitions in the data dictionary. • DML compiler, which translates DML statements in a query language into an evaluation plan consisting of low-level instructions that the query evaluation engine understands. A query can usually be translated into any of a number of alternative evaluation plans that all give the same result. The DML compiler also performs query optimization, that is, it picks the lowest cost evaluation plan from among the alternatives. • Query evaluation engine, which executes low-level instructions generated by the DML compiler. Figure 1.4 shows these components and the connections among them.t
  • 27. Transaction Management • What if the system fails? • What if more than one user is concurrently updating the same data? • A transaction is a collection of operations that performs a single logical function in a database application • Transaction-management component ensures that the database remains in a consistent (correct) state despite system failures (e.g., power failures and operating system crashes) and transaction failures. • Concurrency-control manager controls the interaction among the concurrent transactions, to ensure the consistency of the database.
  • 28. Database Users and Administrators Database
  • 29. DATABASE ADMINISTRATOR A Database Administrator (DBA) in Database Management System (DBMS) is an IT professional who works on creating, maintaining, querying, and tuning the database of the organization. They are also responsible for maintaining data security and integrity. ... They specialize in database development. 1.ROLE OF DBA 1.Defining the Schema 2.System Designer 3.To manage DBMS software and server 4.Deciding storage and Access methods 5. Deciding the hardware device 6. Decides Data Recovery and Back up method 7. Database accessibility 8. Monitoring performance. 9. Decides content of the database