Identify seven key questions that must be answered when designing a database, please explain it in two-three paragraphs with valid references.
Chapter 1 Chapter 1 Database Systems ‹#› After completing this chapter, you will be able to: Define the difference between data and information Describe what a database is, various types, and why they are valuable assets for decision making Explain the importance of database design See how modern databases evolved from file systems Understand flaws in file system data management Outline the main components of the database system Describe the main functions of a database management system (DBMS) Learning Objectives © 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. ‹#› 2 Characteristics of data in today’s world Ubiquitous (i.e., abundant, global, and everywhere) Pervasive (i.e., unescapable, prevalent, and persistent) Databases make data persistent and shareable in a secure way Specialized structures that allow computer-based systems to store, manage, and retrieve data very quickly Why Databases? © 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. ‹#› Data consists of raw facts Not yet processed to reveal meaning to the end user Building blocks of information Information results from processing raw data to reveal meaning Requires context Bedrock of knowledge Should be accurate, relevant, and timely Data versus Information © 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. ‹#› 4 Shared, integrated computer structure that stores data End-user data: raw facts of interest to end user Metadata: data about data, through which the end-user data is integrated and managed Describes data characteristics and relationships Database management system (DBMS) Collection of programs Manages the database structure Controls access to data stored in the database Introducing the Database © 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. ‹#› 5 Database management system (DBMS): intermediary between the user and the database Enables data to be shared Presents the end user with an integrated view of data Provides more efficient and effective data management Improves sharing, security, integration, access, decision-making, productivity, etc. Role and Advantages of the DBMS (1 of 2) © 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. ‹#› 6 Role and Advantages of the DBMS (2 of 2) © 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. ‹#› 7 Single-user database: supports one user at a time Desktop database: single-user database on a personal computer Multiuser database: supports multiple users at the same time Workgroup databases: supports a small number of users or a specific department Enterprise database: supports many users across many departments Types of Databases (1 of 5) © 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. ‹#› 8 Classification by location Centralized database: data located at a single site Distributed database: data distributed across different sites Cloud database: created and maintained using cloud data services that provide defined performance measures for the database Types of Databases (2 of 5) © 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. ‹#› 9 Classification by data type General-purpose database: contains a wide variety of data used in multiple disciplines Discipline-specific database: contains data focused on specific subject areas Operational database: designed to support a company’s day-to-day operations Types of Databases (3 of 5) © 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. ‹#› 10 Analytical database: stores historical data and business metrics used exclusively for tactical or strategic decision making Data warehouse: stores data in a format optimized for decision support Online analytical processing (OLAP): tools for retrieving, processing, and modeling data from the data warehouse Business intelligence: captures and processes business data to generate information that support decision making Types of Databases (4 of 5) © 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. ‹#› 11 Databases can be classified to reflect the degree to which the data is structured Unstructured data exists in its original (raw) state Structured data results from formatting Structure is applied based on type of processing to be performed Semistructured data: processed to some extent Extensible Markup Language (XML) Represents data elements in textual format Types of Databases (5 of 5) © 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. ‹#› 12 Focuses on design of database structure that will be used to store and manage end-user data Well-designed database: facilitates data management and generates accurate and valuable information Poorly designed database: causes difficult-to-trace errors that may lead to poor decision making Why Database Design Is Important © 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. ‹#› 13 Manual file systems Accomplished through a system of file folders and filing cabinets Computerized file systems Data processing (DP) specialist created a computer-based system to track data and produce required reports File system redux: modern end-user productivity tools Includes spreadsheet programs such as Microsoft Excel Evolution of File System Data Processing (1 of 3) © 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. ‹#› Evolution of File System Data Processing (2 of 3) Table 1.2 Basic File Terminology TERMDEFINITION DataRaw 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. FieldA character or group of characters (alphabetic or numeric) that has a specific meaning. A field is used to define and store data. RecordA 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. FileA collection of related records. For example, a file might contain data about the students currently enrolled at Gigantic University. © 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. ‹#› 15 Evolution of File System Data Processing (3 of 3) © 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. ‹#› 16 Problems with file systems challenge the types of information that can be created from data as well as information accuracy Lengthy development times Difficulty of getting quick answers Complex system administration Lack of security and limited data sharing Extensive programming Problems with File System Data Processing © 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. ‹#› 17 Structural dependence Access to a file is dependent on its own structure All file system programs are modified to conform to a new file structure Structural independence File structure is changed without affecting the application’s ability to access the data Structural and Data Dependence (1 of 2) © 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. ‹#› 18 Data dependence Data access changes when data storage characteristics change Data independence Data storage characteristics are changed without affecting the program’s ability to access the data Practical significance of data dependence is the difference between logical and physical format Structural and Data Dependence (2 of 2) © 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. ‹#› 19 Unnecessarily storing the same data at different places Islands of information (i.e., scattered data locations) Increases the probability of having different versions of the same data Data Redundancy (1 of 2) © 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. ‹#› Possible results of uncontrolled data redundancy Poor data security Data inconsistency Data-entry errors Data integrity problems Data Redundancy (2 of 2) © 2019 Cengage. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. ‹#› Develop when not all of the required changes in the redundant data are made