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Chapter 13 Databases and Information Management Chapter 13 Objectives Next p. 13.2 Explain why data and information are important to an organization Explain how to use a query language Identify file maintenance techniques Understand how Web databases work Differentiate between the file processing and database approaches Discuss the responsibilities of the database analysts and administrators Discuss the advantages of using a database management system (DBMS) Identify the qualities of valuable information Describe characteristics of relational and object-oriented databases Describe the various types of information systems Understand the concept of a data warehouse Data and Information How are data and information related? Computers process data into information Data is raw facts; information is data that is organized and meaningful Next p. 13.2 Fig. 13-1 data information Data and Information What is a database? Collection of data organized so you can access, retrieve, and use it Database software allows you to • Create database • Add, change, and delete data • Sort and query database Database software also is called database management system (DBMS) Next p. 13.2 Data and Information What is data integrity? Degree to which data is correct When database contains errors, it loses integrity Garbage in, garbage out (GIGO) Cannot create correct information from incorrect data Next p. 13.3 The Hierarchy of Data What is a field? Combination of one or more characters Smallest unit of data user accesses Field name uniquely identifies each field fields Next p. 13.4 Fig. 13-3 The Hierarchy of Data What are characteristics of a field? Data type Field size Text – letters, numbers, or special characters Numeric – numbers only Currency – dollar and cent amounts or numbers containing decimal values Date – month, day, year, and sometimes time information data types Memo – lengthy text entries Yes/No – only the values Yes or No Hyperlink – Web address that links to a document or a Web page Next p. 13.5 Object – picture, audio, video, or a document created in other applications such as word processing or spreadsheet The Hierarchy of Data What is a record? Group of related fields field names records key field Next p. 13.5 Fig. 13-2 Uniquely identifies each record in file Also called primary key maximum characters in Rating field The Hierarchy of Data What is a data file? Collection of related records stored on disk Each record in file contains same fields Each field contains different data Also called a file Database usually composed of group of related data files fields Sample Customer File Next p. 13.5 Fig. 13-3 records Maintaining Data What is file maintenance? Procedure that keeps data current Adding records Changing records Next p. 13.6 Deleting records Maintaining Data What is validation? Validity check analyzes entered data to help ensure it is correct Click to view Web Link then click Validity Checks Next p. 13.9 Fig. 13-7 Maintaining Data What is a completeness check? Error message displays stating which required fields are blank Next p. 13.10 Fig. 13-8 required information Maintaining Data What is a check digit? Number(s) or character(s) appended to or inserted into primary key value Used to confirm accuracy of primary key value Initial primary key: 1367 Calculate total of digits: 1 + 3 + 6 + 7 = 17 Calculate total of digits again: 1+7=8 Check digit = 8 Next p. 13.10 Resulting primary key: 13678 File Processing Versus Databases What is a file processing system? Each department or area within organization has own set of files Records in one file often do not relate to records in any other file Problem: same customer may have different name or address in each file Next p. 13.11 Fig. 13-9 File Processing Versus Databases What is the database approach? Many programs and users can share data in database Secures data so only authorized users can access certain data items Next p. 13.12 Fig. 13-10 only one customer file in company database File Processing Versus Databases What are the strengths of the database approach? Reduced data redundancy Improved data integrity Shared data Reduced development time Next p. 13.13 Easier reporting File Processing Versus Databases How do a database application and a file processing application differ in the way they might store data? File processing example Next p. 13.13 Fig. 13-11 Database example Database Management Systems What is a database management system (DBMS)? Software that allows you to create, access, and manage a database Click to view animation Click to view Web Link then click Database Managemen t Systems Next p. 13.14 Fig. 13-12 Database Management Systems What is a data dictionary? Contains data about each file in database and each field within those files Click to view Web Link then click Data Dictionary Next p. 13.15 Fig. 13-13 Database Management Systems What is a query language? Simple, English-like statements that allow you to specify data to display, print, or store Next p. 13.16 Fig. 13-14 query results Database Management Systems What is a query by example (QBE)? Program retrieves records that match criteria entered in form fields Next p. 13.17 Fig. 13-15 query by example screen query results Database Management Systems What is a form? Window on screen that provides areas for entering or changing data in database E-form is similar, but used on Web Next p. 13. Fig. 13-16 Database Management Systems What is a report generator? Generates report without user’s knowledge of programming Comes with a database report Next p. 13. 19Fig. 13-18 Database Management Systems What is data security? DBMS provides means to ensure only authorized users can access data with specified privileges Click to view video Next p. 13.19 Access privileges Define activities that specific user or group of users can perform Read-only privileges User can retrieve data, but cannot change it Full-update privileges User can retrieve and change the data Database Management Systems What is a log? Listing of activities that change database contents For every change, DBMS places three items in log file before image: a copy of the customer record prior to the change the actual change of data after image: a copy of the customer record after the change Next p. 13.20 Fig. 13-18 Database Management Systems What is a recovery utility? Next p. 13.20 Uses log file and/or backups to restore database when it is damaged or destroyed Rollforward DBMS uses log to re-enter changes made to database since last save or backup Rollback Also called forward recovery DBMS uses log to undo any changes made to database during a certain period of time Also called backward recovery Relational, Object-Oriented and Multidimensional What is a data model? Databases Every database and DBMS based on specific data model Composed of rules and standards Click to view animation Next p. 13.21 Fig. 13-20 Relational Databases Object-oriented Databases Object-relational Databases Multidimensional Databases Relational, Object-Oriented, and Multidimensional Databases What is a relational database? Stores data in tables that consist of rows and columns • Each row has primary key • Each column has a unique name Relational terminology Click to view Web Link then click Relational Databases Next p. 13.22 Fig. 13-21 Relational, Object-Oriented, and Multidimensional Databases What is normalization? Process designed to ensure data within relations (tables) contains least amount of duplication row column table Next p. 13.22 Fig. 13-22 relationships Relational, Object-Oriented, and Multidimensional Databases What is relational algebra? Uses variables and operations to build new relations Used to manipulate and retrieve data Projection operation Retrieves data from columns (fields) Selection operation Retrieves data from certain rows (records) Join operation Next p. 13.24 Combines data from two or more tables Relational, Object-Oriented, and Multidimensional Databases What is an example of a projection operation? Extracts data from column (field) all rows and columns in Movie table projection operation results Next p. 13.24 Fig. 13-23 Relational, Object-Oriented, and Multidimensional Databases What is an example of a selection operation? Extracts data from a row (record) all rows and columns in Movie table selection operation results Next p. 13.24 Fig. 13-23 Relational, Object-Oriented, and Multidimensional Databases What is an example of a combined projection and selection operation? Extracts data from column (field) for certain rows (records) all rows and columns in Movie table projection and selection operation results Next p. 13.24 Fig. 13-23 Relational, Object-Oriented, and Multidimensional Databases What is an example of a join operation? Combines data from two or more tables using a common column Movie Table Rental Table Rental Table and Movie Table joined on Movie ID Column Next p. 13.24 Fig. 13-24 Relational, Object-Oriented, and Multidimensional Databases What is Structured Query Language (SQL)? Allows you to manage, update, and retrieve data Uses relational algebra Has special keywords and rules included in SQL statements projection operation Click to view Web Link then click SQL join operation selection operation Next p. 13.25 Fig. 13-25 Relational, Object-Oriented, and Multidimensional Databases What is an object-oriented database (OODB)? Stores data in objects Advantages • Can store more types of data • Can access data faster Click to view Web Link then click Object-Oriented Databases Next p. 13.26 Object Item that can contain both data and activities that read or process data Object query language (OQL) Manipulates and retrieves objectoriented and object-relational data Relational, Object-Oriented, and Multidimensional Databases What are examples of applications appropriate for an object-oriented database? Multimedia databases Hypertext databases Store images, audio clips, and/or video clips Contain text links to other documents Groupware databases Hypermedia databases Store documents such as schedules, calendars, manuals, memos, and reports Contain text, graphics, video, and sound Computer-aided design (CAD) databases Next p. 13.26 Store data about engineering, architectural, and scientific designs Web databases Link to e-form on Web page Relational, Object-Oriented, and Multidimensional Databases What is a multidimensional database (MDDB)? Click to view Web Link then click Multidimensional Databases Next p. 13.27 Stores data in dimensions Advantage Can consolidate data much faster than relational database Database Administration What is the role of the database analyst and administrator? Database analyst (DA) Focuses on meaning and usage of data Decides proper placement of fields, defines relationships among data, and identifies users’ access privileges Click to view Web Link then click Database Administrator Next p. 13.30 Database administrator (DBA) Creates and maintains data dictionary, manages database security, monitors database performance, and checks backup and recovery procedures Database Administration What is the role of the employee as a user? Next p. 13.30 Employee should learn how to utilize data in database Take part in designing database that will help achieve company’s overall goals Database Administration What are guidelines for developing a database? Next p. 13.30 Fig. 13-29 Qualities of Valuable Information What are the qualities of valuable information? Accurate Organized Accessible Verifiable Useful Timely Next p. 13.30 Cost-effective Qualities of Valuable Information How do managers use information? 1. objectives; strategies; tactics 2. money; people; management; structure 3. communication; instructions; motivation 4. performance; measurement; corrective action Next p. 13.32 Fig. 13-30 Planning Controlling Organizing Leading Qualities of Valuable Information What are the levels of users? Focus on the company’s overall goals and objectives Applies specific programs and plans necessary to meet the stated objectives Involves day-to-day activities within the company Next p. 13.32 Fig. 13-31 Access information necessary to make decisions – a trend called empowering users Types of Information Systems What is an information system? Set of hardware, software, data, people, and procedures that work together to produce information hardware people procedures Next p. 13.34 Fig. 13-32 software data Types of Information Systems What are the five categories of information systems? Decision support systems Office information systems Management information systems Transaction processing systems Next p. 13.34 Expert systems Types of Information Systems What is a management information system (MIS)? Generates accurate, timely, and organized information Managers and other users can • Make decisions • Solve problems • Supervise activities • Track progress Often integrated with transaction processing systems Next p. 13.36 Types of Information Systems What is a detailed report? Lists one record per line Next p. 13.36 Fig. 13-34 Types of Information Systems What is a summary report? Consolidates data, so you can review it quickly and easily Usually has totals, tables, or graphs Next p. 13.36 Fig. 13-34 Types of Information Systems What is an exception report? Identifies data outside of normal condition Conditions, called exception criteria, define normal activity or status range Next p. 13.36 Fig. 13-34 Types of Information Systems What is a decision support system (DSS)? Helps managers analyze data and make decisions One type of DSS is Click to view Web executive Link information then click Decision Support system (EIS) Systems Next p. 13.37 Fig. 13-35 Types of Information Systems What is a data warehouse? Huge database system that stores and manages data required to analyze historical and current transactions Click to view Web Link then click Data Warehouses Next p. 13.38 Fig. 13-36 Types of Information Systems What are terms associated with a data warehouse? Distributed database Web farming Process of collecting data from Internet as source for data warehouse Data exists in many separate locations throughout network or Internet Data mart Click stream Next p. 13.39 Collection of every action that users make as they move through Web site Smaller version of data warehouse Data mining Process of finding patterns and relationships among data Types of Information Systems What is an expert system? Captures and stores knowledge of human experts Knowledge base Combined subject knowledge and experiences of human experts Inference rules Click to view Web Link then click Artificial Intelligence Next p. 13.40 Set of logical judgments applied to knowledge base each time user describes situation to expert system Types of Information Systems What is an integrated information system? Five information systems combined in some way Decision support systems Office information systems Transaction processing systems Next p. 13.41 Management information systems Expert systems Integrated information system Summary of Databases and Information Management Data and information The hierarchy of data Maintaining data File processing versus databases Database management systems Relational, object-oriented, and multidimensional databases Database administration Qualities of valuable information Types of information systems Chapter 13 Complete