Title DBMS Complete Note.pdf ✅

Prepared by: Raju Poudel [MCA] 2 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 and large businesses It is only limited to smaller DBMS system. 3 Remove redundancy and Integrity Redundancy and Integrity issues 4 Expensive. But in the long term Total Cost of Ownership is cheap It's cheaper 5 Easy to implement complicated transactions No support for complicated transactions
Prepared by: Raju Poudel [MCA] 3 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
Prepared by: Raju Poudel [MCA] 4 Disadvantages of DBMS • Cost of Hardware and Software of a DBMS is quite high which increases the budget of your organization. • Most database management systems are often complex systems, so the training for users to use the DBMS is required. • In some organizations, all data is integrated into a single database which can be damaged because of electric failure or database is corrupted on the storage media • Use of the same program at a time by many users sometimes lead to the loss of some data. • DBMS can't perform sophisticated calculations Application of DBMS SN Sector Use of DBMS 1 Banking For customer information, account activities, payments, deposits, loans, etc. 2 Airlines For reservations and schedule information. 3 Universities For student information, course registrations, colleges and grades. 4 Telecommunication It helps to keep call records, monthly bills, maintaining balances, etc. 5 Finance For storing information about stock, sales, and purchases of financial instruments like stocks and bonds. 6 Sales Use for storing customer, product & sales information. 7 Manufacturing It is used for the management of supply chain and for tracking production of items. Inventories status in warehouses. 8 HR Management For information about employees, salaries, payroll, deduction, generation of paychecks, etc.
Prepared by: Raju Poudel [MCA] 5 UNIT II – Database Design, Architecture & Model – 6 HRS Overview of Database Design Process Database systems are designed to manage large bodies of information. Database design mainly involves the design of the database schema. The design of a complete database application environment that meets the needs of the enterprise being modeled requires attention to a broader set of issues. In this text, we focus initially on the writing of database queries and the design of database schemas. Database Design is a collection of processes that facilitate the designing, development, implementation and maintenance of database systems. It helps produce database systems 1. That meet the requirements of the users 2. Have high performance. • A high-level data model provides the database designer with a conceptual framework in which to specify the data requirements of the database users, and how the database will be structured to fulfill these requirements. • The initial phase of database design, then, is to characterize fully the data needs of the prospective database users. The database designer needs to interact extensively with domain experts and users to carry out this task. The outcome of this phase is a specification of user requirements. • Next, the designer chooses a data model, and by applying the concepts of the chosen data model, translates these requirements into a conceptual schema of the database. • The schema developed at this conceptual-design phase provides a detailed overview of the enterprise. The designer reviews the schema to confirm that all data requirements are indeed satisfied and are not in conflict with one another. The designer can also examine the design to remove any redundant features. The focus at this point is on describing the data and their relationships, rather than on specifying physical storage details. • In terms of the relational model, the conceptual-design process involves decisions on what attributes we want to capture in the database and how to group these attributes to form the various tables.