DBMS CH1 Questions and answers 2023

DBMS CH1 Questions and answers 2023Define each of the following terms: a. data b. field c. record d. file A. Data- Raw facts, such as a telephone number, a birth date, a customer name, and a year-to-date (YTD) sales value. Data has little meaning unless it has been organized in some logical manner B. Field- A character or group of characters (alphabetic or numeric) that has a specific meaning. A field is used to define and store data. C. Record - A logically connected set of one or more fields that describes a person, place, or thing. For example, the fields that constitute a record for a customer might consist of the customer's name, address, phone number, date of birth, credit limit, and unpaid balance. D. File- A collection of related records. For example, a file might contain data about the students currently enrolled at Gigantic University. What is data redundancy, and which characteristics of the file system can lead to it? Data redundancy exists when the same data is stored unnecessarily at different places. The file system's structure makes it difficult to combine data from multiple sources. The organizational structure promotes the storage of the same basic data in different locations. The dispersion of data is exacerbated by the use of spreadsheets to store data. In a file system, the entire sales department would share access to the SALES data file through the data management and reporting programs created by the DP specialist. With the use of spreadsheets, each member of the sales department can create his or her own copy of the sales data. Because data stored in different locations will probably not be updated consistently, the islands of information often contain different versions of the same data. What is data independence, and why is it lacking in file systems? Data independence is a condition in which data access is unaffected by changes in the physical data storage characteristics. In a file system, making changes to an existing file structure requires multiple steps including: 1. Read a record from the original file 2. Transform the original data to conform to the new structure's storage requirements 3. Write the transformed data into the new file structure 4. Repeat the preceding steps for each record in the original file. Because all data access programs are subject to change when any of the file's data storage characteristics change (that is, changing the data type), the file system is said to exhibit data dependence. What is a DBMS, and what are its functions? A database management system (DBMS) is a collection of programs that manages the database structure and controls access to the data stored in the database. DBMS functions: 1. Data dictionary management: The DBMS uses the data dictionary to look up the required data component structures and relationships, thus relieving you from having to code such complex relationships in each program. Additionally, any changes made in a database structure are automatically recorded in the data dictionary, thereby freeing you from having to modify all of the programs that access the changed structure. In other words, the DBMS provides data abstraction, and it removes structural and data dependence from the system. 2. Data storage management: The DBMS creates and manages the complex structures required for data storage, thus relieving you from the difficult task of defining and programming the physical data characteristics. 3. Data transforming and presentation: The DBMS transforms entered data to conform to required data structures. The DBMS relieves you of the chore of distinguishing between the logical data format and the physical data format. That is, the DBMS formats the physically retrieved data to make it conform to the user's logical expectations. 4. Security management: The DBMS creates a security system that enforces user security and data privacy. 5. Multiuser access control: To provide data integrity and data consistency, the DBMS uses sophisticated algorithms to ensure that multiple users can access the database concurrently without compromising its integrity. 6. Backup and recovery management: The DBMS provides backup and data recovery to ensure data safety and integrity. 7. Data integrity management: The DBMS promotes and enforces integrity rules, thus minimizing data redundancy and maximizing data consistency. 8. Database access languages and application programming interfaces: The DBMS provides data access through a query language. Structured Query Language (SQL) is the de facto query language and data access standard supported by the majority of DBMS vendors. 9. Database communication interfaces: A current-generation DBMS accepts end- user requests via multiple, different network environments. What is structural independence, and why is it important? Structural independence exists when you can change the file structure without affecting the application's ability to access the data. What is the role of a DBMS, and what are its advantages? What are its disadvantages? DBMS roles: 1. Improved data sharing 2. Improved data security 3. Better data integration 4. Minimized data inconsistency 5. Improved data access 6. Improved decision making 7. Increased end-user productivity List and describe the different types of databases. 1. Single-user database: A database that supports only one user at a time 2. Multiuser database: A database that supports multiple concurrent users. 3. Desktop database: A single-user database that runs on a personal computer. 4. Workgroup database: A multiuser database that usually supports fewer than 50 users or is used for a specific department in an organization. 5. Enterprise database: Database that is used by the entire organization and supports many users (more than 50, usually hundreds) across many departments 6. Centralized database: A database located at a single site. 7. Distributed database: A logically related database that is stored in two or more physically independent sites. 8. Cloud database: A database that is created and maintained using cloud services, such as Microsoft Azure or Amazon AWS. 9. General-purpose database: A database that contains a wide variety of data used in multiple disciplines. 10. Discipline-specific database: A database that contains data focused on specific subject areas. 11. Operational database: A database designed primarily to support a company's day-to-day operations. 12. Analytical database: A database focused primarily on storing historical data and business metrics used for tactical or strategic decision making.