Tiêu đề DBMS Complete Note.pdf ✅

WWW.BCANOTESNEPAL.COM APP ALSO AVALIABLE ON PLAYSTORE Database Management SystFourth SEMESTER Database Management System Complete Notes Visit www.bcanotesnepal.com and for Android Application from Playstore “BCA Notes Nepal” Notes Prepared By Raju Poudel MCA, Purbanchal University
WWW.BCANOTESNEPAL.COM APP ALSO AVALIABLE ON PLAYSTORE
WWW.BCANOTESNEPAL.COM APP ALSO AVALIABLE ON PLAYSTORE UNIT I – INTRODUCTION TO DBMS – 3 HRS DBMS Overview • A database management system (DBMS) is a software package designed to define, manipulate, retrieve and manage data in a database. • A DBMS generally manipulates the data itself, the data format, field names, record structure and file structure. It also defines rules to validate and manipulate this data. • A DBMS relieves users of framing programs for data maintenance. Fourth- generation query languages, such as SQL, are used along with the DBMS package to interact with a database. • Some other DBMS examples include: MySQL, SQL Server, Oracle, dBASE, FoxPro, MS-Access etc. Database • A database is a collection of information that is organized so that it can be easily accessed, managed and updated. Data is organized into rows, columns and tables, and it is indexed to make it easier to find relevant information. Characteristics of DBMS • Provides security and removes redundancy (duplication) • Insulation between programs and data abstraction • Support of multiple views of the data • Sharing of data and multiuser transaction processing • DBMS allows entities and relations among them to form tables. • It follows the ACID concept (Atomicity, Consistency, Isolation, and Durability). • DBMS supports multi-user environment that allows users to access and manipulate data in parallel. DBMS vs. Flat File SN DBMS Flat File Management System 1 Multi-user access It does not support multi-user access 2 Design to fulfill the need for small It is only limited to smaller DBMS system. and large businesses 3 Remove redundancy and Integrity Redundancy and Integrity issues 4 Expensive. But in the long term It's cheaper Total Cost of Ownership is cheap 5 Easy to implement complicated No support for complicated transactions transactions
WWW.BCANOTESNEPAL.COM APP ALSO AVALIABLE ON PLAYSTORE Objective of DBMS 1. Eliminate redundant data. 2. Make access to the data easy for the user. 3. Provide for mass storage of relevant data. 4. Protect the data from physical harm and un-authorized systems. 5. Allow for growth in the data base system. 6. Make the latest modifications to the data base available immediately. 7. Allow for multiple users to be active at one time. 8. Provide prompt response to user requests for data. Importance of DBMS • A database management system is important because it manages data efficiently and allows users to perform multiple tasks with ease. • A database management system stores, organizes and manages a large amount of information within a single software application. Use of this system increases efficiency of business operations and reduces overall costs. • Database management systems are important to businesses and organizations because they provide a highly efficient method for handling multiple types of data. • Some of the data that are easily managed with this type of system include: employee records, student information, payroll, accounting, project management, inventory and library books. These systems are built to be extremely versatile. • Without database management, tasks have to be done manually and take more time. Data can be categorized and structured to suit the needs of the company or organization. • Data is entered into the system and accessed on a routine basis by assigned users. Each user may have an assigned password to gain access to their part of the system. Multiple users can use the system at the same time in different ways. Advantages of DBMS • DBMS offers a variety of techniques to store & retrieve data • DBMS serves as an efficient handler to balance the needs of multiple applications using the same data • Application programmers never exposed to details of data representation and storage. • A DBMS uses various powerful functions to store and retrieve data efficiently. • Offers Data Integrity and Security • The DBMS implies integrity constraints to get a high level of protection against prohibited access to data. • A DBMS schedules concurrent access to the data in such a manner that only one user can access the same data at a time • Reduced Application Development Time