The document provides an introduction to advanced database systems, including basic definitions such as database, data, information, metadata, and database management system. It describes the typical components and functionality of a database management system, including data models, data manipulation languages, data definition languages, storage management, transaction management, and more. The document also discusses database users, advantages of databases, SQL, the query processor, and database architecture types.
This document defines database and DBMS, describes their advantages over file-based systems like data independence and integrity. It explains database system components and architecture including physical and logical data models. Key aspects covered are data definition language to create schemas, data manipulation language to query data, and transaction management to handle concurrent access and recovery. It also provides a brief history of database systems and discusses database users and the critical role of database administrators.
This document defines database and DBMS, describes their advantages over file-based systems like data independence and integrity. It explains database system components and architecture including physical and logical data models. Key aspects covered are data definition language to create schemas, data manipulation language to query data, and transaction management to handle concurrent access and recovery. It also provides a brief history of database systems and discusses database users and the critical role of database administrators.
This document provides an overview of database management systems. It defines key concepts like what is a database, database system components, and why databases are used. It describes drawbacks of using file systems to store data that databases address. It also explains the three architecture levels (external, conceptual, internal), database users and administrators, and classifications of DBMSs.
This document provides an overview of key concepts in database management systems including:
1. It discusses different data models including relational, entity-relationship, and object-oriented models.
2. It describes database system components like data definition language, data manipulation language, and transaction management.
3. It outlines different types of users that interact with database systems and roles like database administrators.
This document provides an overview of database management systems (DBMS). It discusses what a DBMS is, common database applications, the benefits of using a DBMS like data independence and integrity, and the different levels of abstraction in a DBMS. It also summarizes key DBMS concepts like data models, schemas, languages for querying and manipulating data, and the roles of database administrators.
Introduction to database systems
Database size and complexity
What is DBMS?
Characteristics of Database approach
Users of database
Advantages of using database system
Database systems evolution
When not to use database systems
The document provides an overview of database management systems (DBMS). It discusses DBMS applications, why DBMS are used, different users of databases, data models and languages like SQL. It also summarizes key components of a DBMS including data storage, query processing, transaction management and database architecture.
The document discusses key concepts related to database management systems (DBMS). It defines a database as a collection of related data used to solve an institution's data management needs. A DBMS is software that allows users to define, create, maintain and control access to the database. The document outlines the differences between data and databases, as well as the characteristics and components of a DBMS, including different views (physical, conceptual, external) of databases. It also discusses data modeling concepts such as entities, attributes, keys, and different types of data models (conceptual, logical, physical).
This document defines database and DBMS, describes their advantages over file-based systems like data independence and integrity. It explains database system components and architecture including physical and logical data models. Key aspects covered are data definition language to create schemas, data manipulation language to query data, and transaction management to handle concurrent access and recovery. It also provides a brief history of database systems and discusses database users and the critical role of database administrators.
This document defines database and DBMS, describes their advantages over file-based systems like data independence and integrity. It explains database system components and architecture including physical and logical data models. Key aspects covered are data definition language to create schemas, data manipulation language to query data, and transaction management to handle concurrent access and recovery. It also provides a brief history of database systems and discusses database users and the critical role of database administrators.
This document provides an overview of database management systems. It defines key concepts like what is a database, database system components, and why databases are used. It describes drawbacks of using file systems to store data that databases address. It also explains the three architecture levels (external, conceptual, internal), database users and administrators, and classifications of DBMSs.
This document provides an overview of key concepts in database management systems including:
1. It discusses different data models including relational, entity-relationship, and object-oriented models.
2. It describes database system components like data definition language, data manipulation language, and transaction management.
3. It outlines different types of users that interact with database systems and roles like database administrators.
This document provides an overview of database management systems (DBMS). It discusses what a DBMS is, common database applications, the benefits of using a DBMS like data independence and integrity, and the different levels of abstraction in a DBMS. It also summarizes key DBMS concepts like data models, schemas, languages for querying and manipulating data, and the roles of database administrators.
Introduction to database systems
Database size and complexity
What is DBMS?
Characteristics of Database approach
Users of database
Advantages of using database system
Database systems evolution
When not to use database systems
The document provides an overview of database management systems (DBMS). It discusses DBMS applications, why DBMS are used, different users of databases, data models and languages like SQL. It also summarizes key components of a DBMS including data storage, query processing, transaction management and database architecture.
The document discusses key concepts related to database management systems (DBMS). It defines a database as a collection of related data used to solve an institution's data management needs. A DBMS is software that allows users to define, create, maintain and control access to the database. The document outlines the differences between data and databases, as well as the characteristics and components of a DBMS, including different views (physical, conceptual, external) of databases. It also discusses data modeling concepts such as entities, attributes, keys, and different types of data models (conceptual, logical, physical).
This document provides an introduction to database management systems (DBMS). It defines a database as an organized collection of data and explains that a DBMS is software that allows for the storage, organization, and retrieval of data from a database. The document then discusses different database models including hierarchical, network, relational, and object-oriented models. It provides examples and discusses advantages and disadvantages of each model.
The document provides an introduction to database management systems. It discusses key concepts such as the purpose of DBMSs, data models, database languages, database design, storage and query processing. It also describes common DBMS components like the data dictionary and different types of database users. Overall, the document serves as a high-level overview of database management systems and lays the foundation for further exploration of topics within this domain.
The document provides an introduction to database management systems (DBMS) and database models. It defines key terms like data, database, DBMS, file system vs DBMS. It describes the evolution of DBMS from 1960 onwards and different database models like hierarchical, network and relational models. It also discusses the roles of different people who work with databases like database designers, administrators, application programmers and end users.
This document provides an overview of database management systems and the normalization process. It begins with definitions of data hierarchy and traditional file processing approaches. It then describes the benefits of a database approach using a DBMS, including features like querying, backup/replication, and security. Components of a DBMS are explained, including data definition languages, data manipulation languages, and the data dictionary. Common data models like hierarchical, network, relational, and object models are also summarized. The document concludes by defining key concepts in normalization like functional dependencies and normal forms, and providing an overview of the normalization process.
This document provides an introduction to database management systems (DBMS). It discusses what a DBMS is, common database applications, and drawbacks of using file systems to store data that DBMS aim to address, such as data redundancy, integrity issues, and concurrent access problems. It also summarizes key components of a DBMS, including its logical and physical levels of abstraction, data models, data definition and manipulation languages, storage management, query processing, transaction management, and common database architectures.
The document provides an overview of database management systems (DBMS). It discusses that a DBMS contains organized data about an enterprise. It offers advantages over file systems like avoiding data redundancy and inconsistencies. The document describes database applications, levels of abstraction in a DBMS, the relational data model using tables and SQL, and components of the database engine like storage management, query processing, and transaction management. It also provides a brief history of database systems from the 1950s to modern times.
This document provides an introduction to database systems for a BS in IT degree. It discusses key concepts like the difference between data and information, the historical roots of databases in file systems, database management systems and their functions, different database models including hierarchical, network and relational models, and the evolution of database models over time. It also defines important terms and describes the roles of different users in a database system environment.
DBMS UNIT_1: Introduction Application of DMBS,
Advantages & Disadvantages.
Internal Level/Schema
Conceptual Level/Schema
Physical Level/Schema
Logical Data Independence
Physical Data Independence
Role of DBA
Type of Database user
The document discusses database management systems and data modeling. It begins by defining key terms like data, databases, database management systems, and data models. It then provides a brief history of database development from the 1960s to the 1980s. The rest of the document discusses database concepts in more detail, including components of a DBMS, types of database users, database administration responsibilities, data modeling techniques, and the evolution of different data models.
The document provides an overview of database management systems and related concepts. It discusses database components like the data dictionary and data repository. It also covers different data models including hierarchical, network, and relational models. Key concepts covered include entities, attributes, relationships, schemas, and data abstraction which allows users to interact with data without knowing details of how it is structured and stored.
Week 1 Before the Advent of Database Systems & Fundamental Conceptsoudesign
This document provides an introduction to databases. It begins by defining a database as a self-describing collection of integrated tables that store data and relationships. It then contrasts database systems with earlier file-based systems, noting advantages like reduced data redundancy and improved data integrity in database systems. The document proceeds to define key database concepts like tables, rows, columns and indexing.
This document provides an overview of database management systems and related concepts. It discusses data hierarchy, traditional file processing, the database approach to data management, features and capabilities of database management systems, database schemas, components of database management systems, common data models including hierarchical, network, and relational models, and the process of data normalization.
This document discusses data, information, databases, database management systems (DBMS), and the architecture of DBMS. It defines data as raw unorganized facts and information as processed data that provides meaning. A database is a shared collection of interrelated data designed to meet an organization's information needs. A DBMS is a collection of programs used to create and maintain a database. The document then describes the components of a typical DBMS architecture including the query processor, file manager, data manager, and data dictionary. It also discusses database users such as administrators, designers, analysts, and various types of end users.
Database Management System IntroductionSmriti Jain
The document discusses key concepts in databases including:
- Data refers to raw facts and details, while entities are things that data describes with attributes.
- A record combines all details of an entity, files group related records, and a database collects logically related files and records.
- A database management system (DBMS) enables users to define, create and maintain databases and provides flexible data management.
- DBMS benefits include centralized data control, consistency, sharing, and independence from applications.
Database systems allow for centralized management of shared data through database management systems (DBMS). This document outlines key concepts in database systems including common uses of databases, characteristics of file-based systems, problems with the file approach, definitions of database and DBMS, typical DBMS functions, DBMS components, and advantages/disadvantages of DBMS. It also provides examples of database uses and describes the typical makeup of a database including data, records, fields, and other components.
The document discusses database concepts including:
1. The relationship between data and information and how computers process data into meaningful information.
2. What a database is and how it allows users to organize, access, and use data through database management systems.
3. The process of conceptual and physical database design including entity-relationship modeling and normalization.
The document provides an overview of database management systems and the relational model. It discusses key concepts such as:
- The structure of relational databases using relations, attributes, tuples, domains, and relation schemas.
- Entity-relationship modeling and the relational algebra operations used to manipulate relational data, including selection, projection, join, and set operations.
- Additional relational concepts like primary keys, foreign keys, and database normalization to reduce data redundancy and inconsistencies.
The summary captures the main topics and essential information about database systems and the relational model covered in the document in 3 sentences.
This document provides an introduction to database concepts. It discusses the limitations of file-based systems, including data redundancy, lack of data sharing, and inconsistent data updates across programs. These issues are addressed by the database approach, which involves centralized data storage and a database management system (DBMS) to control access. Key advantages of the database approach include data independence, reduced redundancy, improved integrity and security. The document also outlines the typical components and roles involved in a DBMS environment.
This document provides an introduction to database management systems (DBMS). It defines a database as an organized collection of data and explains that a DBMS is software that allows for the storage, organization, and retrieval of data from a database. The document then discusses different database models including hierarchical, network, relational, and object-oriented models. It provides examples and discusses advantages and disadvantages of each model.
The document provides an introduction to database management systems. It discusses key concepts such as the purpose of DBMSs, data models, database languages, database design, storage and query processing. It also describes common DBMS components like the data dictionary and different types of database users. Overall, the document serves as a high-level overview of database management systems and lays the foundation for further exploration of topics within this domain.
The document provides an introduction to database management systems (DBMS) and database models. It defines key terms like data, database, DBMS, file system vs DBMS. It describes the evolution of DBMS from 1960 onwards and different database models like hierarchical, network and relational models. It also discusses the roles of different people who work with databases like database designers, administrators, application programmers and end users.
This document provides an overview of database management systems and the normalization process. It begins with definitions of data hierarchy and traditional file processing approaches. It then describes the benefits of a database approach using a DBMS, including features like querying, backup/replication, and security. Components of a DBMS are explained, including data definition languages, data manipulation languages, and the data dictionary. Common data models like hierarchical, network, relational, and object models are also summarized. The document concludes by defining key concepts in normalization like functional dependencies and normal forms, and providing an overview of the normalization process.
This document provides an introduction to database management systems (DBMS). It discusses what a DBMS is, common database applications, and drawbacks of using file systems to store data that DBMS aim to address, such as data redundancy, integrity issues, and concurrent access problems. It also summarizes key components of a DBMS, including its logical and physical levels of abstraction, data models, data definition and manipulation languages, storage management, query processing, transaction management, and common database architectures.
The document provides an overview of database management systems (DBMS). It discusses that a DBMS contains organized data about an enterprise. It offers advantages over file systems like avoiding data redundancy and inconsistencies. The document describes database applications, levels of abstraction in a DBMS, the relational data model using tables and SQL, and components of the database engine like storage management, query processing, and transaction management. It also provides a brief history of database systems from the 1950s to modern times.
This document provides an introduction to database systems for a BS in IT degree. It discusses key concepts like the difference between data and information, the historical roots of databases in file systems, database management systems and their functions, different database models including hierarchical, network and relational models, and the evolution of database models over time. It also defines important terms and describes the roles of different users in a database system environment.
DBMS UNIT_1: Introduction Application of DMBS,
Advantages & Disadvantages.
Internal Level/Schema
Conceptual Level/Schema
Physical Level/Schema
Logical Data Independence
Physical Data Independence
Role of DBA
Type of Database user
The document discusses database management systems and data modeling. It begins by defining key terms like data, databases, database management systems, and data models. It then provides a brief history of database development from the 1960s to the 1980s. The rest of the document discusses database concepts in more detail, including components of a DBMS, types of database users, database administration responsibilities, data modeling techniques, and the evolution of different data models.
The document provides an overview of database management systems and related concepts. It discusses database components like the data dictionary and data repository. It also covers different data models including hierarchical, network, and relational models. Key concepts covered include entities, attributes, relationships, schemas, and data abstraction which allows users to interact with data without knowing details of how it is structured and stored.
Week 1 Before the Advent of Database Systems & Fundamental Conceptsoudesign
This document provides an introduction to databases. It begins by defining a database as a self-describing collection of integrated tables that store data and relationships. It then contrasts database systems with earlier file-based systems, noting advantages like reduced data redundancy and improved data integrity in database systems. The document proceeds to define key database concepts like tables, rows, columns and indexing.
This document provides an overview of database management systems and related concepts. It discusses data hierarchy, traditional file processing, the database approach to data management, features and capabilities of database management systems, database schemas, components of database management systems, common data models including hierarchical, network, and relational models, and the process of data normalization.
This document discusses data, information, databases, database management systems (DBMS), and the architecture of DBMS. It defines data as raw unorganized facts and information as processed data that provides meaning. A database is a shared collection of interrelated data designed to meet an organization's information needs. A DBMS is a collection of programs used to create and maintain a database. The document then describes the components of a typical DBMS architecture including the query processor, file manager, data manager, and data dictionary. It also discusses database users such as administrators, designers, analysts, and various types of end users.
Database Management System IntroductionSmriti Jain
The document discusses key concepts in databases including:
- Data refers to raw facts and details, while entities are things that data describes with attributes.
- A record combines all details of an entity, files group related records, and a database collects logically related files and records.
- A database management system (DBMS) enables users to define, create and maintain databases and provides flexible data management.
- DBMS benefits include centralized data control, consistency, sharing, and independence from applications.
Database systems allow for centralized management of shared data through database management systems (DBMS). This document outlines key concepts in database systems including common uses of databases, characteristics of file-based systems, problems with the file approach, definitions of database and DBMS, typical DBMS functions, DBMS components, and advantages/disadvantages of DBMS. It also provides examples of database uses and describes the typical makeup of a database including data, records, fields, and other components.
The document discusses database concepts including:
1. The relationship between data and information and how computers process data into meaningful information.
2. What a database is and how it allows users to organize, access, and use data through database management systems.
3. The process of conceptual and physical database design including entity-relationship modeling and normalization.
The document provides an overview of database management systems and the relational model. It discusses key concepts such as:
- The structure of relational databases using relations, attributes, tuples, domains, and relation schemas.
- Entity-relationship modeling and the relational algebra operations used to manipulate relational data, including selection, projection, join, and set operations.
- Additional relational concepts like primary keys, foreign keys, and database normalization to reduce data redundancy and inconsistencies.
The summary captures the main topics and essential information about database systems and the relational model covered in the document in 3 sentences.
This document provides an introduction to database concepts. It discusses the limitations of file-based systems, including data redundancy, lack of data sharing, and inconsistent data updates across programs. These issues are addressed by the database approach, which involves centralized data storage and a database management system (DBMS) to control access. Key advantages of the database approach include data independence, reduced redundancy, improved integrity and security. The document also outlines the typical components and roles involved in a DBMS environment.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
हिंदी वर्णमाला पीपीटी, hindi alphabet PPT presentation, hindi varnamala PPT, Hindi Varnamala pdf, हिंदी स्वर, हिंदी व्यंजन, sikhiye hindi varnmala, dr. mulla adam ali, hindi language and literature, hindi alphabet with drawing, hindi alphabet pdf, hindi varnamala for childrens, hindi language, hindi varnamala practice for kids, https://www.drmullaadamali.com
Main Java[All of the Base Concepts}.docxadhitya5119
This is part 1 of my Java Learning Journey. This Contains Custom methods, classes, constructors, packages, multithreading , try- catch block, finally block and more.
Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
"Learn about all the ways Walmart supports nonprofit organizations.
You will hear from Liz Willett, the Head of Nonprofits, and hear about what Walmart is doing to help nonprofits, including Walmart Business and Spark Good. Walmart Business+ is a new offer for nonprofits that offers discounts and also streamlines nonprofits order and expense tracking, saving time and money.
The webinar may also give some examples on how nonprofits can best leverage Walmart Business+.
The event will cover the following::
Walmart Business + (https://business.walmart.com/plus) is a new shopping experience for nonprofits, schools, and local business customers that connects an exclusive online shopping experience to stores. Benefits include free delivery and shipping, a 'Spend Analytics” feature, special discounts, deals and tax-exempt shopping.
Special TechSoup offer for a free 180 days membership, and up to $150 in discounts on eligible orders.
Spark Good (walmart.com/sparkgood) is a charitable platform that enables nonprofits to receive donations directly from customers and associates.
Answers about how you can do more with Walmart!"
বাংলাদেশের অর্থনৈতিক সমীক্ষা ২০২৪ [Bangladesh Economic Review 2024 Bangla.pdf] কম্পিউটার , ট্যাব ও স্মার্ট ফোন ভার্সন সহ সম্পূর্ণ বাংলা ই-বুক বা pdf বই " সুচিপত্র ...বুকমার্ক মেনু 🔖 ও হাইপার লিংক মেনু 📝👆 যুক্ত ..
আমাদের সবার জন্য খুব খুব গুরুত্বপূর্ণ একটি বই ..বিসিএস, ব্যাংক, ইউনিভার্সিটি ভর্তি ও যে কোন প্রতিযোগিতা মূলক পরীক্ষার জন্য এর খুব ইম্পরট্যান্ট একটি বিষয় ...তাছাড়া বাংলাদেশের সাম্প্রতিক যে কোন ডাটা বা তথ্য এই বইতে পাবেন ...
তাই একজন নাগরিক হিসাবে এই তথ্য গুলো আপনার জানা প্রয়োজন ...।
বিসিএস ও ব্যাংক এর লিখিত পরীক্ষা ...+এছাড়া মাধ্যমিক ও উচ্চমাধ্যমিকের স্টুডেন্টদের জন্য অনেক কাজে আসবে ...
This presentation was provided by Steph Pollock of The American Psychological Association’s Journals Program, and Damita Snow, of The American Society of Civil Engineers (ASCE), for the initial session of NISO's 2024 Training Series "DEIA in the Scholarly Landscape." Session One: 'Setting Expectations: a DEIA Primer,' was held June 6, 2024.
How to Fix the Import Error in the Odoo 17Celine George
An import error occurs when a program fails to import a module or library, disrupting its execution. In languages like Python, this issue arises when the specified module cannot be found or accessed, hindering the program's functionality. Resolving import errors is crucial for maintaining smooth software operation and uninterrupted development processes.
LAND USE LAND COVER AND NDVI OF MIRZAPUR DISTRICT, UPRAHUL
This Dissertation explores the particular circumstances of Mirzapur, a region located in the
core of India. Mirzapur, with its varied terrains and abundant biodiversity, offers an optimal
environment for investigating the changes in vegetation cover dynamics. Our study utilizes
advanced technologies such as GIS (Geographic Information Systems) and Remote sensing to
analyze the transformations that have taken place over the course of a decade.
The complex relationship between human activities and the environment has been the focus
of extensive research and worry. As the global community grapples with swift urbanization,
population expansion, and economic progress, the effects on natural ecosystems are becoming
more evident. A crucial element of this impact is the alteration of vegetation cover, which plays a
significant role in maintaining the ecological equilibrium of our planet.Land serves as the foundation for all human activities and provides the necessary materials for
these activities. As the most crucial natural resource, its utilization by humans results in different
'Land uses,' which are determined by both human activities and the physical characteristics of the
land.
The utilization of land is impacted by human needs and environmental factors. In countries
like India, rapid population growth and the emphasis on extensive resource exploitation can lead
to significant land degradation, adversely affecting the region's land cover.
Therefore, human intervention has significantly influenced land use patterns over many
centuries, evolving its structure over time and space. In the present era, these changes have
accelerated due to factors such as agriculture and urbanization. Information regarding land use and
cover is essential for various planning and management tasks related to the Earth's surface,
providing crucial environmental data for scientific, resource management, policy purposes, and
diverse human activities.
Accurate understanding of land use and cover is imperative for the development planning
of any area. Consequently, a wide range of professionals, including earth system scientists, land
and water managers, and urban planners, are interested in obtaining data on land use and cover
changes, conversion trends, and other related patterns. The spatial dimensions of land use and
cover support policymakers and scientists in making well-informed decisions, as alterations in
these patterns indicate shifts in economic and social conditions. Monitoring such changes with the
help of Advanced technologies like Remote Sensing and Geographic Information Systems is
crucial for coordinated efforts across different administrative levels. Advanced technologies like
Remote Sensing and Geographic Information Systems
9
Changes in vegetation cover refer to variations in the distribution, composition, and overall
structure of plant communities across different temporal and spatial scales. These changes can
occur natural.
Exploiting Artificial Intelligence for Empowering Researchers and Faculty, In...Dr. Vinod Kumar Kanvaria
Exploiting Artificial Intelligence for Empowering Researchers and Faculty,
International FDP on Fundamentals of Research in Social Sciences
at Integral University, Lucknow, 06.06.2024
By Dr. Vinod Kumar Kanvaria
How to Manage Your Lost Opportunities in Odoo 17 CRMCeline George
Odoo 17 CRM allows us to track why we lose sales opportunities with "Lost Reasons." This helps analyze our sales process and identify areas for improvement. Here's how to configure lost reasons in Odoo 17 CRM
2. Basic Definitions
Database: Organized collection of logically
related data.
Data: Known facts that can be recorded and
have an implicit meaning.
Structured: numbers, text, dates
Unstructured: images, video, documents
Information: data processed to increase
knowledge in the person using the data
Metadata: data that describes the properties
and context of user data.
Monday, July 17, 2023
Advanced Database Systems 2
3. Basic Definitions
Database Management System (DBMS): A
software package/ system to facilitate the
creation and maintenance of a computerized
database.
Database System: The DBMS software
together with the data itself. Sometimes, the
applications are also included.
Monday, July 17, 2023
Advanced Database Systems 3
4. Why study database management?
Critical to business, government, science, culture, society
Determines success of many corporations (even their
existence)
Many tech companies built on data management (Google,
Amazon, Yahoo!, Facebook, …)
Other companies offer database products (Microsoft, IBM,
Oracle)
Database systems span major areas of computer science
Operating systems (file, memory, process management)
Theory (languages, algorithms, complexity)
Artificial Intelligence (knowledge-based systems, logic, search)
Software Engineering (application development)
Data structures (trees, hashtables)
Monday, July 17, 2023
Advanced Database Systems 4
5. Regularly Structured Data
Sets the structure once (e.g., table attributes) and then
has many instances (records) that use that structure
Examples of regularly structured data
Employee, payroll, bank account, Data captured on web
forms
DBMS or RDBMS mainly designed to store, manage,
and retrieve structured data
Examples of unstructured (loosely or “semistructured”)
data
Documents, video, audio, images, maps, …
Managed mainly by content management and
information retrieval systems
Monday, July 17, 2023
Advanced Database Systems 5
6. File Management Systems
A File is un-interpreted, unstructured collection
of information
File operations: delete, catalog, create, rename,
open, close, read, write, find, …
Access methods: Algorithms to implement
operations along with internal file organization
Examples: File of Customers, File of Students;
Access method: implementation of a set of
operations on a file of students or customers.
Monday, July 17, 2023
Advanced Database Systems 6
7. File Management System Problems
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) become
“buried” in program code rather than being stated
explicitly
Hard to add new constraints or change existing ones
Monday, July 17, 2023
Advanced Database Systems 7
8. File Management System Problems
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 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
Monday, July 17, 2023
Advanced Database Systems 8
9. Problems with Data Redundancy
Waste of space to have duplicate data
Causes more maintenance headaches
The biggest problem:
o Data changes in one file could cause
inconsistencies
o Compromises in data integrity
9 Monday, July 17, 2023
Advanced Database Systems 9
10. SOLUTION:
The DATABASE Approach
Central repository of shared data
Data is managed by a controlling agent
Stored in a standardized, convenient form
10
Requires a Database Management System (DBMS)
Order Filing
System
Invoicing
System
Payroll
System
DBMS
Central database
Contains employee,
order, inventory,
pricing, and
customer data
Monday, July 17, 2023
Advanced Database Systems 10
11. 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
Monday, July 17, 2023
Advanced Database Systems 11
12. Typical DBMS Functionality
Define a database : in terms of data types,
structures and constraints
Construct or Load the Database on a secondary
storage medium
Manipulating the database : querying,
generating reports, insertions, deletions and
modifications to its content
Concurrent Processing and Sharing by a set of
users and programs – yet, keeping all data valid
and consistent.
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13. Advantages of Using Databases
Controlling redundancy in data storage and in
development and maintenance efforts.
Sharing of data among multiple users.
Restricting unauthorized access to data.
Providing persistent storage for program
Objects (in Object-oriented DBMS’s)
Providing Storage Structures for efficient Query
Processing
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14. Advantages of Using Databases
Providing backup and recovery services.
Providing multiple interfaces to different classes
of users.
Representing complex relationships among
data.
Enforcing integrity constraints on the database.
Drawing Inferences and Actions using rules
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15. Database Users
End users
Use the database system to achieve some goal. They use
the data for queries, reports and may update the database
content.
Application developers
Write software to allow end users to interface with the
database system
Database systems programmer
Writes the database software itself
They define the content, the structure, the constraints, and
functions or transactions against the database.
They must communicate with the end-users and understand
their needs.
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16. DB Users: Database Administrator
Coordinates all the activities of the database system;
has a good understanding of the enterprise’s
information resources and needs.
Database administrator's duties include:
Schema definition
Storage structure and access method definition
Schema and physical organization modification
Granting user authority to access the database
Specifying integrity constraints
Acting as liaison with users
Monitoring performance and responding to changes in
requirements
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17. Data Models
A collection of tools for describing
Data
Data relationships
Data semantics
Data constraints
Relational model: Information is stored as tuples or
records in relations or tables
Entity-Relationship data model (mainly for database
design)
Object-based data models (Object-oriented and
Object-relational)
Semi-structured data model (XML)
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18. Data Manipulation Language (DML)
Language for accessing and manipulating the data
organized by the appropriate data model
DML also known as query language
Two classes of languages
Procedural – user specifies what data is required and
how to get the data
Declarative (nonprocedural) – user specifies what data
is required without specifying how to get the data
SQL is the most widely used query language
SQL Statements: SELECT, INSERT, UPDATE,
DELETE, MERGE
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19. Data Definition Language (DDL)
Specification notation for defining the database schema
Example: create table instructor (
ID char(5),
name varchar(20),
dept_name varchar(20),
salary numeric(8,2))
SQL Statements include:
CREATE
ALTER
DROP
RENAME
TRUNCATE
COMMENT
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20. Data Definition Language (DDL)
DDL compiler generates a set of table templates
stored in a data dictionary
Data dictionary contains metadata (i.e., data about
data). It stores information about the database
itself
The dictionary holds
Descriptions of database objects (tables, users,
rules, views, indexes,…)
Information about who is using which data
(locks)
Schemas and mappings
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21. SQL
SQL: widely used non-procedural language
Example: Find the name of the instructor with ID 22222
select name
from instructor
where instructor.ID = ‘22222’
Example: Find the ID and building of instructors in the Physics
dept.
select instructor.ID, department.building
from instructor, department
where instructor.dept_name = department.dept_name and
department.dept_name = ‘Physics’
Application programs generally access databases through one of
Language extensions to allow embedded SQL
Application program interface (e.g., ODBC/JDBC) which allow
SQL queries to be sent to a database
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22. Query Processor
Compiler – verifies whether a program or
query is written in accordance with DDL and
DML rules
Optimizer – Finds the most effective way to
access the required data and supply it in a
user requested form. Monitors the query
execution and modifies a query evaluation
plan if necessary
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23. Transaction Management
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.
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24. 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 for the
following tasks:
interaction with the file manager
efficient storing, retrieving and updating of
data.
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25. File Manager
File Manager is responsible for mapping
logical database units (objects, relations,
etc.) into a set of low level files.
It is responsible for maintenance of files and
indexes on them. It should be able to create
and destroy index and collect unused
storage space to eliminate any unneeded
gaps on disks.
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26. Buffer Manager
Buffer Manager is responsible for the allocation
and maintenance buffer space in memory to
facilitate processing database data by several
concurrent applications.
Buffer Manager decides when to load data from
a buffer to a database or discard the data and
under what conditions a new data should be put
into a buffer
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27. Database Architecture
The architecture of a database system is
greatly influenced by the underlying computer
system on which the database is running:
Centralized
Client-server
Parallel (multi-processor)
Distributed
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