Chapter 13 Databases and Information Management

Chapter 13 Databases and Information Management

Chapter 13 Objectives 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 Next Understand the concept of a data warehouse p. 13.2

Data and Information What is data?
A collection of raw unprocessed facts, figures, and symbols Next p Fig. 13-1

Data and Information What is information?
Data that is organized, meaningful, and useful Next p Fig. 13-1

Data and Information How are data and information related?
Computers process data into information Next p Fig. 13-1

Data and Information What is a database?
Includes a collection of data organized so you can access, retrieve, and use the data Database software allows you to Create a computerized database Add, change, and delete data Sort and retrieve data from the database Create forms and reports for the data in the database Database software also called a database management system (DBMS) Next p. 13.2

You cannot create correct information from data that is incorrect
Data and Information What is data integrity? The degree to which data is correct When a database contains errors, it loses integrity Very important because computers and people use information to make decisions and take actions Garbage in, garbage out (GIGO) You cannot create correct information from data that is incorrect Next p. 13.3

A number (4), letter (R), punctuation mark (?), or other symbol (&)
The Hierarchy of Data What is a field? Character A number (4), letter (R), punctuation mark (?), or other symbol (&) A combination of one or more characters The smallest unit of data a user accesses A field name uniquely identifies each field fields Next p Fig. 13-3

The Hierarchy of Data What are characteristics of a field?
Text – letters, numbers, or special characters Data type Specifies the kind of data a field can contain Specifies how the field is used Field size Defines the maximum number of characters a field can contain Numeric – numbers only Currency – dollar and cent amounts or numbers containing decimal values Date – month, day, year, and sometimes time information Memo – lengthy text entries Yes/No – only the values Yes or No Hyperlink – Web address that links to a document or a Web page Object – picture, audio, video, or a document created in other applications such as word processing or spreadsheet Next p. 13.5

The Hierarchy of Data What is a record? A group of related fields
field names maximum characters in Rating field records key field A field that uniquely identifies each record in a file Also called a primary key Next p Fig. 13-2

The Hierarchy of Data What is a data file? Also called a file
A collection of related records stored on a disk Each record in the file contains the same fields Each field contains different data fields Sample Customer File records Next p Fig. 13-3

Maintaining Data What is file maintenance?
Also called data maintenance The procedures that keep data current Adding records Changing records Deleting records Next p. 13.6

Maintaining Data How are records added?
A clerk uses a Customer Maintenance program to add a new record The clerk enters the data for each field of the record The clerk takes a photograph with a digital camera and confirms the data is correct The clerk then adds the record to the database file Next p Fig. 13-4

Maintaining Data How are records changed?
The clerk starts the Customer Maintenance program The clerk displays the customer record on the screen The clerk makes the corrections The clerk verifies the data and then clicks the Save button to change the record in the Customer file Records changed to correct inaccurate data or to update old data with new data Next p Fig. 13-5

Maintaining Data How is data deleted?
A record can be flagged, or marked, so the program will not process it again How is data deleted? The clerk starts the Customer Maintenance program The clerk displays the customer record on the screen The clerk confirms the correct customer record displays The clerk clicks the Delete Record button Next p Fig. 13-6

Maintaining Data What is validation?
The process of comparing data to a set of rules or values to find out if the data is correct A validity check analyzes entered data to help ensure that it is correct Validity checks are also called validation rules Click to view Web Link then click Validity Checks Next p Fig. 13-7

Maintaining Data What are the types of validity checks?
Alphabetic check Ensures that you enter only alphabetic data into a field Numeric check Ensures that you enter only numeric data into a field Completeness check Verifies a required field contains data Range check Determines whether a number is within a specified range Consistency check Tests if the data in two or more associated fields is logical Check digit Confirms the accuracy of a primary key value Next p. 13.9

Maintaining Data What is an example of a completeness check?
If you do not fill in a required field, an error message usually displays stating which required fields you left blank Next p Fig. 13-8

Maintaining Data What is a check digit?
A number(s) or character(s) that is appended to or inserted into a primary key value Used to confirm the accuracy of a primary key value When the primary key is entered, the program applies the check digit formula to determine if the primary key is valid Initial primary key: 1367 Calculate total of digits: = 17 Calculate total of digits again: 1 + 7 = 8 Check digit = 8 Next Resulting primary key: 13678 p

File Processing Versus Databases
What is a file processing system? Each department or area within an organization has its own set of files Records in one file often do not relate to the records in any other file Next p Fig. 13-9

What are the weaknesses of a file processing system? isolated data It is often difficult to access data stored in many files across several departments Sharing data from multiple, separate files is often a complicated procedure data redundancy The files often store the same fields in multiple files Wastes resources such as storage space and people’s time Requires a larger storage capacity Compromises data integrity Next p

What is the database approach? Back end The application that supports the front end Many programs and users can share the data in the database Secures the data so only authorized users can access certain data items Front end A program that typically has a more user-friendly interface than the DBMS Next p Fig

What are the strengths of the database approach? Reduced data redundancy Improved data integrity Shared data Reduced development time Easier reporting Next p

How do a database application and a file processing application differ in the way they might store data? File processing example Database example Next p Fig

Database Management Systems
What is a database management system (DBMS)? Software that allows you to create, access, and manage a database Available for many sizes and types of computers Click to view animation Click to view Web Link then click Database Management Systems Next p Fig

What is a data dictionary? Also called a repository Contains data about each file in the database and each field within those files Sometimes called metadata because it contains data about data Click to view Web Link then click Data Dictionary Next p Fig

What is a default value for a field? A value that the DBMS initially displays in a field Data dictionary allows you to specify a default value for a field Next p

What is a query? Query language A request for specific data from the database Four commonly used methods to access data Query by example Form Click to view animation Report generator Next p

What is a query language? Consists of simple, English-like statements that allow you to specify the data to display, print, or store query results wizard for querying the database Next p Fig

What is a query by example (QBE)? The program retrieves records that match criteria you enter in the form fields Uses a graphical user interface query by example screen query results Next p Fig

What is a form? Sometimes called a data entry form A window on the screen that provides areas for entering or changing data in a database Next p. 13. Fig

What is an electronic form? Also called an e-form A form that sends entered data across a network or the Internet Typically uses a means to secure the data while it is transported Next p Fig

What is a report generator? Also called a report writer Allows you to design a report on the screen, retrieve data into the report design, and then display or print the report Usually allows you to format page numbers and dates; titles and column headings; subtotals and totals; and fonts, font sizes, color, and shading Next p Fig

What is data security? A DBMS provides means to make certain only authorized users can access data at permitted times Most DBMSs allow you to identify different levels of access privileges for each field in the database Access privileges Define the activities that a 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 Click to view video Next p

How should you protect data stored in a database? Backup On a regular basis, make a backup, or copy, of the entire database A DBMS provides a variety of techniques to restore a database to a usable form in case it is damaged or destroyed Some DBMSs have their own backup utilities Next p

What is a log? A listing of activities that change the contents of the database For every change the DBMS places three items in the log 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 Fig

What is a recovery utility? Rollforward Also called forward recovery The DBMS uses the log to re-enter changes made to the database since the last save or backup Uses the logs and/or backups to restore a database when it is damaged or destroyed Restores the database using rollback and rollforward techniques Rollback Also called backward recovery The DBMS uses the log to undo any changes made to the database during a certain period of time Next p

Relational, Object-Oriented and Multidimensional Databases
What is a data model? Every database and DBMS is based on a specific data model Consists of rules and standards that define how the database organizes data Defines how users view the organization of the data Three popular data models in use today Object-relational databases combine features of the relational and object-oriented data models Relational Databases Object-oriented Databases Click to view animation Object-relational Databases Next Multidimensional Databases p Fig

Company on the Cutting Edge
Oracle products are used by 96 percent of the Fortune 500 companies In 1977, Larry Ellison co-founded Oracle Now the world’s leading supplier of software for e-business Its database product, also named Oracle, is the world’s leading database software Click to view video Click to view Web Link then click Oracle Corporation Next p

Technology Trailblazer
E. F. Codd In 1970, he created the relational approach to database management Codd’s model continues to serve as the de facto standard on which large and small databases are structured Click to view Web Link then click E. F. Codd Next p

Relational, Object-Oriented, and Multidimensional Databases
What is a relational database? Stores data in tables that consist of rows and columns Each row has a primary key and each column has a unique name A relational database uses terms different from a file processing environment Data terminology Click to view Web Link then click Relational Databases Next p Fig

What is a relationship? A connection within the data Relationships stored as part of a relational database Normalization is a process designed to make sure the data within the relations (tables) contains the least amount of duplication row column table Next relationships p Fig

What is relational algebra? Projection operation Retrieves data from columns (fields) Uses variables and operations to build new relations Used to manipulate and retrieve data Variables are the tables, rows, and columns of the database Selection operation Retrieves data from certain rows (records) Join operation Combines the data from two or more tables Next p

What is an example of a projection operation? The operation extracts data from a column (field) all rows and columns in Movie table projection operation results Next p Fig

What is an example of a selection operation? The operation extracts data from a row (record) all rows and columns in Movie table selection operation results Next p Fig

What is an example of a combined projection and selection operation? The operation extracts data from a column (field) all rows and columns in Movie table projection and selection operation results Next p Fig

What is an example of a join operation? Combines the data from two or more tables using a common column Rental Table Movie Table Rental Table and Movie Table Joined on Movie ID Column Next p Fig

What is Structured Query Language (SQL)? A query language that allows you to manage, update, and retrieve data Uses relational algebra Has special keywords and rules that you include in SQL statements projection operation Click to view Web Link then click SQL join operation selection operation Next p Fig

What is an object-oriented database (OODB)? Object An item that can contain both data and the activities that read or process the data Stores data in objects Advantages Can store more types of data Can access the data faster Object query language (OQL) Query language used to manipulate and retrieve object-oriented and object-relational data Click to view Web Link then click Object-Oriented Databases Next p

What are examples of applications appropriate for an OODB? Multimedia databases Store images, audio clips, and/or video clips Hypertext databases Contain text links to other documents Groupware databases Store documents such as schedules, calendars, manuals, memos, and reports Hypermedia databases Contain text, graphics, video, and sound Computer-aided design (CAD) databases Store data about engineering, architectural, and scientific designs Web databases Link to an e-form on a Web page Next p

What is an example of a hypermedia database? To display information about a particular artifact, you enter its description in the Keywords text box Keywords text box Next p Fig

What is a multidimensional database (MDDB)? Advantage It can consolidate data much faster than a relational database Stores data in dimensions Can store more than two dimensions of data Sometimes known as a hypercube Click to view Web Link then click Multidimensional Databases Next p

Web Databases What is a Web database?
A database of information that can be accessed through the Web A vast amount of information available through the Web Click to view video Next p Fig

Company on the Cutting Edge
A free, national directory of U.S. residential information Among the 50 most popular Internet sites Contains telephone number and address directories for nearly 100- million people, 12-million businesses, and 4-million U.S. addresses Click to view Web Link then click Switchboard Next p

Web Databases How can you access a Web database?
Step 2: The Web server sends the search text through a CGI program to the database. The database retrieves the Web page that contains the search text and sends it through the CGI program back to the Web server. Step 1 Step 2 CGI (Common Gateway Interface) script A type of program that manages the sending and receiving of data between the front end and the database server Database server A computer that stores and provides access to the database Step 1: The browser sends your search text to the Web server. Step 1 Step 3: The Web server sends the Web page to the browser. Step 1 Step 2 Step 3 How can you access a Web database? Next p Fig

Database Administration
What is the role of the database analyst and administrator? Database analyst (DA) Also called data modeler Focuses on the meaning and usage of data Decides the proper placement of fields, defines relationships among data, and identifies users’ access privileges Responsible for managing and coordinating all database activities In small companies, one person often is both the database analyst and administrator Database administrator (DBA) Creates and maintains the data dictionary, manages security of the database, monitors the performance of the database, and checks backup and recovery procedures Click to view Web Link then click Database Administrator Next p

What is the role of the employee as a user? Employee should learn how to utilize the data in the database Must take an active role in identifying new data for the database Take part in designing the database that will help achieve company’s overall goals Next p

What are guidelines for developing a database? Next p Fig

Qualities of Valuable Information
What are the qualities of valuable information? Characteristics of information make it valuable Accurate information Organized information Verifiable Accessible information Useful information Timely information Cost-effective information Next p

How do managers use information? Controlling Planning Organizing Leading Planning Organizing Leading Organizing Planning Planning Managers are responsible for coordinating the use of resources Resources include people, money, materials, and information Perform four activities performance measurement corrective action communication instructions motivation money people management structure objectives strategies tactics Next p Fig

What are the levels of users? Involves day-to-day activities within the company Access information necessary to make decisions – a trend called empowering users Access information necessary to make decisions – a trend called empowering users Applies specific programs and plans necessary to meet the stated objectives Access information necessary to make decisions – a trend called empowering users Involves day-to-day activities within the company Focus on the company’s overall goals and objectives Access information necessary to make decisions – a trend called empowering users Involves day-to-day activities within the company Applies specific programs and plans necessary to meet the stated objectives The types of information you need often depend on your employee level in the company Next p Fig

Technology Trailblazer
Larry Ellison Oracle chairman and co-founder Uncanny ability to motivate his employees and partners toward a common vision Co-founded Oracle in 1977 Goal is to grow Oracle into the largest software company in the world Click to view Web Link then click Larry Ellison Next p

Types of Information Systems
What is an information system? A set of hardware, software, data, people, and procedures that work together to produce information Procedure An instruction, or set of instructions, a user follows to accomplish an activity hardware people procedures Next p Fig software data

What are the five categories of information systems? Office information systems Decision support systems Management information systems Transaction processing systems Expert systems Next p

What is an office information system (OIS)? Increases employee productivity and assists with communications among employees Often described as office automation Next p

What is a transaction processing system (TPS)? Captures and processes data from day-to-day business activities Includes several business activities Recording a business activity Confirming an action or causing a response Maintaining data, which involves adding new data, changing existing data, or removing unwanted data Next p Fig

What are forms of transaction processing systems? Batch processing The computer collects data over a period of time and processes all transactions later, as a group Used by first TSPs Initially referred to as data processing Intent of earliest TPSs was to process faster, reduce clerical costs, and improve customer service Online transaction processing (OLTP) The computer processes each transaction as it is entered Most transaction processing systems today use OLTP Next p

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

What are the three basic types of information created by an MIS? Detailed report Usually just lists transactions Next p Fig

What are the three basic types of information created by an MIS? Summary report Consolidates data, so you can review it quickly and easily Usually has totals, tables, or graphs Next p Fig

What are the three basic types of information created by an MIS? Exception report Identifies data outside of a normal condition Conditions, called exception criteria, define the normal activity or status range Next p Fig

What is a decision support system (DSS)? Online analytical processing (OLAP) Programs that analyze data and process many records at a time Helps you analyze data and make decisions A variety of DSSs exist Some are company specific Others are available to everyone on the Web Uses data from internal sources From within a company Uses data from external sources From outside a company MOLAP OLAP applications that use multidimensional databases Click to view Web Link then click Decision Support Systems ROLAP OLAP applications that use relational databases Next p

What is an executive information system (EIS)? A special type of DSS Supports the strategic information needs of executive management Presents information as charts and tables that show trends, ratios, and statistics Next p Fig

What is a data warehouse? A huge database system that stores and manages the data required to analyze historical and current transactions The data can come from internal or external sources Click to view Web Link then click Data Warehouses Next p Fig

What are terms associated with a data warehouse? Distributed database Data exists in many separate locations throughout the network or the Internet Web farming The process of collecting data from the Internet as a source for the data warehouse Data mart Smaller version of a data warehouse Click stream A collection of every action that users make as they move though a Web site Data mining Process of finding patterns and relationships among data Next p

What is an expert system? Knowledge base The combined subject knowledge and experiences of human experts Captures and stores the knowledge of human experts Imitates human reasoning and decision making Two main components One part of a branch of computer science called artificial intelligence (AI) The application of human intelligence to computes Inference rules A set of logical judgments that are applied to the knowledge base each time a user describes a situation to the expert system Click to view Web Link then click Artificial Intelligence Next p

How does an expert system work? Step 4: Choose your price range. Step 5: Review the list of recommendations from Ida. Step 3: Specify the level of security you want while on the cordless phone. Step 2: Indicate where you intend to use the phone. Step 1: Select the item you wish to purchase (cordless phone, in this case.) Click to view Web Link then click Expert Systems Next p Fig

What is an integrated information system? It is often difficult to classify an information system as belonging to only one of the five types of information systems Office information systems Decision support systems Integrated information system Management information systems Transaction processing systems Expert systems Next p

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 Web databases Database administration Qualities of valuable information Types of information systems

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