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Chapter 7Storing Organizational Information - Databases1CLASSROOM OPENERGREAT BUSINESS DECISIONS Edgar Codds Relational Database TheoryEdgar Frank Codd was born at Portland, Dorset, in England. He studied mathematics and chemistry at Exeter College, Oxford, before serving as a pilot in the Royal Air Force during the Second World War. In 1948, he moved to New York to work for IBM as a mathematical programmer. In 1953 Codd moved to Ottawa, Canada. A decade later he returned to the USA and received his doctorate in computer science from the University of Michigan in Ann Arbor. Two years later he moved to San Jose, California to work at IBM's Almaden Research Center.In the 1960s and 1970s he worked out his theories of data arrangement, issuing his paper "A Relational Model of Data for Large Shared Data Banks" in 1970, after an internal IBM paper one year earlier. To his disappointment, IBM proved slow to exploit his suggestions until commercial rivals started implementing them.Initially, IBM refused to implement the relational model in order to preserve revenue from IMS/DB. Codd then showed IBM customers the potential of the implementation of its model, and they in turn pressured IBM. Then IBM included in its Future System project a System R subproject but put in charge of it were developers who were not thoroughly familiar with Codd's ideas, and isolated the team from Codd. As a result, they did not use Codd's own Alpha language but created a non-relational one, SEQUEL. Even so, SEQUEL was so superior to pre-relational systems that it was copied, based on pre-launch papers presented at conferences, by Larry Ellison in his Oracle DBMS, which actually reached market before SQL/DS due to the then-already proprietary status of the original moniker, SEQUEL had been renamed SQL.Codd continued to develop and extend his relational model, sometimes in collaboration with Chris Date. One of the normalized forms, the Boyce-Codd Normal Form, is named after Codd. Codd also coined the term OLAP and wrote the twelve laws of online analytical processing, although these were never truly accepted after it came out that his white paper on the subject was paid for by a software vendor. Edgar F. Codd died of heart failure at his home in Williams Island, Florida at the age of 79 on Friday, April 18, 2003.Learning Outcomes7.1 Define the fundamental concepts of the relational database model

7.2 Evaluate the advantages of the relational database model

7.3 Compare relational integrity constraints and business-critical integrity constraints27.1 Define the fundamental concepts of the relational database modelThe relational database model stores information in the form of logically related two-dimensional tablesEntities, attributes, primary keys, and foreign keys are all fundamental concepts included in the relational database model7.2 Evaluate the advantages of the relational database modelDatabase advantages from a business perspective includeIncreased flexibilityIncreased scalability and performanceReduced information redundancyIncreased information integrity (quality)Increased information security7.3 Compare operational integrity constraints and business-critical integrity constraintsOperational integrity constraints are rules that enforce basic and fundamental information-based constraintsBusiness-critical integrity constraints are rules that enforce business rules vital to an organizations success and often require more insight and knowledge than operational integrity constraintsLearning Outcomes7.4Describe the benefits of a data driven Web site

7.5 Describe the two primary methods for integrating information across multiple databases37. 4 Describe the benefits of a data-driven Web site.A data-driven Web site is an interactive Web site kept constantly updated and relevant to the needs of its customers through the use of a database. Data-driven Web sites are especially useful when the site offers a great deal of information, products, or services. Web site visitors are frequently angered if they are buried under an avalanche of information when searching a Web site. A data-driven Web site invites visitors to select and view what they are interested in by inserting a query, which the Web site then analyzes and custom builds a Web page in real-time that satisfies the query.

7.5 Describe the two primary methods for integrating information across multiple databases.Forward integration takes information entered into a given system and sends it automatically to all downstream systems and processes.Backward integration takes information entered into a given system and sends it automatically to all upstream systems and processes.

Relational Database FundamentalsInformation is everywhere in an organization

Information is stored in databasesDatabase maintains information about various types of objects (inventory), events (transactions), people (employees), and places (warehouses)

4How many of you are familiar with databases?What kinds of databases can be found around your college?Student registrationCourse evaluationPayrollParking servicesExplain to your students that almost every business decision is based on informationThe information required to make these decisions is typically stored in databasesRelational Database Fundamentals Database models include: Hierarchical database model information is organized into a tree-like structure (using parent/child relationships) in such a way that it cannot have too many relationships Network database model a flexible way of representing objects and their relationships Relational database model stores information in the form of logically related two-dimensional tables5Most organizations use the relational database modelThis text focuses on the relational database modelDiscuss the Coca-Cola Bottling Company of Egypt example in the textHierarchical Structure

Network Structure

Relational Structure

Entities and Attributes Entity a person, place, thing, transaction, or event about which information is stored The rows in each table contain the entities In Figure 7.1 CUSTOMER includes Daves Sub Shop and Pizza Palace entities

Attributes (fields, columns) characteristics or properties of an entity class The columns in each table contain the attributes In Figure 7.1 attributes for CUSTOMER include Customer ID, Customer Name, Contact Name

9This text focuses on the relational database modelReview Figure 7.1What kinds of additional entity classes might be found in this database?INVENTORY, MARKETING CAMPAIGN, SALES QUOTE, INVOICE, PAYMENTWhat kinds of additional entities might be found in the CUSTOMER table?Could include any additional customer Joes Mexican Restaurant, Fitness Forever, and Summers Flower Shop (these are all fictitious)

Review Figure 7.1What kinds of additional attributes might be found in the CUSTOMER table for Daves Sub Shop?Could include any additional customer information:AddressFaxE-mailCell phone

Keys and Relationships Primary keys and foreign keys identify the various entity classes (tables) in the database Primary key a field (or group of fields) that uniquely identifies a given entity in a table Foreign key a primary key of one table that appears an attribute in another table and acts to provide a logical relationship among the two tables

10Review Figure 7.1Explain to your students that the logic that correlates the tables is implemented through the primary keysFor example: Hawkins Shipping in the DISTRIBUTOR table has a primary key called Distributor ID DEN8001Notice that Hawkins Shipping (Distributor ID DEN8001) is responsible for delivering orders 34561 and 345652Therefore, Distributor ID in the ORDER table creates a logical relationship (who shipped what order) between ORDER and DISTRIBUTOR

Keys and Relationships Potential relational database for Coca-Cola

11Walk your students through the relational database model in Figure 7.1To ensure your students are grasping the concepts, ask them to answer the following:How many orders have been placed for Ts Fun Zone? Ans: 1 Order IT 34563How many orders have been placed for Pizza Palace? Ans: NoneHow many items are included in Daves Sub Shops two orders? Ans: Order 34561 has 3 items and order 34562 has one item for a total of 4 items in both orders.Who is responsible for distributing Daves Sub Shops orders? Ans: Hawkins ShippingWhich products are included in Order 34562? Ans: 300 Vanilla Coke Relational Database Advantages Database advantages from a business perspective include Increased flexibility Increased scalability and performance Reduced information redundancy Increased information integrity (quality) Increased information security12All of the above are discussed in the following slides:A good way to explain databases is to compare them to spreadsheetsWhat are the limitations when using a spreadsheet?Limited number of rows and columns (Excel - 65,536 rows by 256 columns) Once you use more than 65,536 rows you have outgrown your spreadsheetOnly one users can access the spreadsheetUsers can view all information in the spreadsheetUsers can change all information in the spreadsheetAll of the disadvantages associated with a spreadsheet are fixed when using a databaseThese advantages are discussed in detail over the next several slidesIncreased Flexibility A well-designed database should: Handle changes quickly and easily Provide users with different views Have only one physical viewPhysical view deals with the physical storage of information on a storage device eg hard disk Have multiple logical viewsLogical view focuses on how users logically access information Eg: a mail-order buss- 2 people view diff format (logical views) but same physical view13The separation between logical and physical views is what allows each user to access database information differentlyWhat would happen if a new database called RealData hit the market and allowed only one logical view?The RealData database simply would never sell. With only one logical view every person in an entire organization would have the same viewDefine two database views for your schools student database (one for students, and one for instructors)What does the student view display when a student accesses the schools student database?Courses enrolledGradesTuitionCredits for graduationWhat does the instructor view display when an instructor accesses the schools student database?Courses teachingStudents in each coursePayment informationVacation timeIncreased Scalability and Performance A database must scale to meet increased demand, while maintaining acceptable performance levels Scalability refers to how well a system can adapt to increased demands Performance measures how quickly a system performs a certain process or transaction14What happens to a business if its suddenly experienced a 60 percent growth in sales and its IT systems fail with all of the increased activity?Remind your students that a big part of developing successful IT systems is being able to anticipate future growth

CLASSROOM EXERCISEBuilding an ER DiagramBreak your students into groups and ask them to create an entity relationship diagram similar to the one in Figure 7.1 for a company or product of their choice. If the students are uncomfortable with databases, you should recommend that they stick to a company similar to the TCCBCE, perhaps a snack food producer, mountain bike equipment producer, or even a footwear producer. If your students are more comfortable with databases, ask them to choose a company that would challenge them such as a fast food restaurant, online book seller, or even a universitys course registration system. The important part of this exercise is for your students to begin to understand how the tables in a database relate. Be sure their ER diagrams include primary keys and foreign keys. Have your students present their ER diagrams to the class and ask the students to find any potential errors with the diagrams.Reduced Information Redundancy Databases reduce information redundancy Redundancy the duplication of information or storing the same information in multiple places

Inconsistency is one of the primary problems with redundant information-difficult to decide which is most current and most accurate15One of the primary goals of a database is to eliminate information redundancy by recording each piece of information in only one placeThis is a good time to tie the discussion back to the material in the previous chapter, low quality informationRecall what happens when a single customer is stored twice with different phone numbers, addresses, or order information in a single databaseIncrease Information Integrity (Quality) Information integrity measures the quality of information

Integrity constraint rules that help ensure the quality of information Relational integrity constraint-rule that enforces basic and fundamental information-based constraints Eg. Users cannot create an order for a nonexistent customer, provide a markup percentage that was negative etc

16Relational integrity constraint rule that enforces basic and fundamental information-based constraintsBusiness-critical integrity constraint rule that enforce business rules vital to an organizations success and often require more insight and knowledge than relational integrity constraints

Can you define two relational integrity constraints for an ordering system?Users cannot create an order for a nonexistent customerAn order cannot be shipped without an addressCan you define two business-critical integrity constraints for an ordering system?Product returns are not accepted for fresh product 15 days after purchaseA discount maximum of 20 percent

Business-critical integrity constraint -rule that enforce business rules vital to an organizations success and often require more insight and knowledge than relational integrity constraints Eg. Product returns are not accepted for fresh product 15 days after purchase,

Increased Information Security Information is an organizational asset and must be protected

Databases offer several security features including: Password provides authentication of the user Access level determines who has access to the different types of information Access control determines types of user access, such as read-only access18Why you would want to define access level security?Access levels will typically mimic the hierarchical structure of the organization and protect organizational information from being viewed and manipulated by individuals who should not have access to the sensitive or confidential informationLow level employees typically have the lowest levels of accessHigh level employees typically have access to all types of database informationFor example: You would not want analysts viewing all salary information for the entire company - in general:Analysts can usually only view their own salaryManagers have higher access and can view the salaries of all their team members, but cannot view other managers salariesDirectors can view all of their managers and analysts salaries, but not other directors salariesThe CFO and CEO can view every employees salaryDatabase Management Systems Database management systems (DBMS) software through which users and application programs interact with a database

19Discuss the two primary forms of user interaction with a databaseDirect interaction The user interacts directly with the DBMSThe DBMS obtains the information from the databaseIndirect interaction User interacts with an application (i.e., payroll application, manufacturing application, sales application)The application interacts with the DBMSThe DBMS obtains the information from the database

DATA-DRIVEN WEB SITES Data-driven Web sites an interactive Web site kept constantly updated and relevant to the needs of its customers through the use of a database

A data-driven Web site is an interactive Web site kept constantly updated and relevant to the needs of its customers through the use of a database. Data-driven Web sites are especially useful when the site offers a great deal of information, products, or services. Web site visitors are frequently angered if they are buried under an avalanche of information when searching a Web site. A data-driven Web site invites visitors to select and view what they are interested in by inserting a query, which the Web site then analyzes and custom builds a Web page in real-time that satisfies the query. The figure displays a Wikipedia user querying business intelligence and the database sending back the appropriate Web page that satisfies the users request

Ask your students what would happen to a Web site that is not data-driven?The users would need to continually update the Web site data manually as the business data is updated. This would be a redundant effort and most likely result in errors and the Web site could quickly become out of sync with the business data

20Data-Driven Web Site Business Advantages Development: Allows the Web site owner to make changes any timeall without having to rely on a developer or knowing HTML programming. A well-structured, data-driven Web site enables updating with little or no training. Content management: A static Web site requires a programmer to make updates. This adds an unnecessary layer between the business and its Web content, which can lead to misunderstandings and slow turnarounds for desired changes. Future expandability: Having a data-driven Web site enables the site to grow faster than would be possible with a static site. Changing the layout, displays, and functionality of the site (adding more features and sections) is easier with a data-driven solution.

Data Driven Web Site AdvantagesDevelopment: Allows the Web site owner to make changes any timeall without having to rely on a developer or knowing HTML programming. A well-structured, data-driven Web site enables updating with little or no training.Content management: A static Web site requires a programmer to make updates. This adds an unnecessary layer between the business and its Web content, which can lead to misunderstandings and slow turnarounds for desired changes.Future expandability: Having a data-driven Web site enables the site to grow faster than would be possible with a static site. Changing the layout, displays, and functionality of the site (adding more features and sections) is easier with a data-driven solution.Minimizing human error: Even the most competent programmer charged with the task of maintaining many pages will overlook things and make mistakes. This will lead to bugs and inconsistencies that can be time consuming and expensive to track down and fix. Unfortunately, users who come across these bugs will likely become irritated and may leave the site. A well-designed, data-driven Web site will have error trapping mechanisms to ensure that required information is filled out correctly and that content is entered and displayed in its correct format.Cutting production and update costs: A data-driven Web site can be updated and published by any competent data entry or administrative person. In addition to being convenient and more affordable, changes and updates will take a fraction of the time that they would with a static site. While training a competent programmer can take months or even years, training a data entry person can be done in 30 to 60 minutes.More efficient: By their very nature, computers are excellent at keeping volumes of information intact. With a data-driven solution, the system keeps track of the templates, so users do not have to. Global changes to layout, navigation, or site structure would need to be programmed only once, in one place, and the site itself will take care of propagating those changes to the appropriate pages and areas. A data-driven infrastructure will improve the reliability and stability of a Web site, while greatly reducing the chance of breaking some part of the site when adding new areas.Improved Stability: Any programmer who has to update a Web site from static templates must be very organized to keep track of all the source files. If a programmer leaves unexpectedly, it could involve re-creating existing work if those source files cannot be found. Plus, if there were any changes to the templates, the new programmer must be careful to use only the latest version. With a data-driven Web site, there is peace of mind, knowing the content is never losteven if your programmer is.21 Minimizing human error: Even the most competent programmer charged with the task of maintaining many pages will overlook things and make mistakes. This will lead to bugs and inconsistencies that can be time consuming and expensive to track down and fix. Unfortunately, users who come across these bugs will likely become irritated and may leave the site. A well-designed, data-driven Web site will have error trapping mechanisms to ensure that required information is filled out correctly and that content is entered and displayed in its correct format. Cutting production and update costs: A data-driven Web site can be updated and published by any competent data entry or administrative person. In addition to being convenient and more affordable, changes and updates will take a fraction of the time that they would with a static site. While training a competent programmer can take months or even years, training a data entry person can be done in 30 to 60 minutes. More efficient: By their very nature, computers are excellent at keeping volumes of information intact. With a data-driven solution, the system keeps track of the templates, so users do not have to. Global changes to layout, navigation, or site structure would need to be programmed only once, in one place, and the site itself will take care of propagating those changes to the appropriate pages and areas. A data-driven infrastructure will improve the reliability and stability of a Web site, while greatly reducing the chance of breaking some part of the site when adding new areas. Improved Stability: Any programmer who has to update a Web site from static templates must be very organized to keep track of all the source files. If a programmer leaves unexpectedly, it could involve re-creating existing work if those source files cannot be found. Plus, if there were any changes to the templates, the new programmer must be careful to use only the latest version. With a data-driven Web site, there is peace of mind, knowing the content is never losteven if your programmer is.Data-Driven Business Intelligence BI in a data-driven Web site

Companies can gain business intelligence by viewing the data accessed and analyzed from their Web site. The figure displays how running queries or using analytical tools, such as a Pivot Table, on the database that is attached to the Web site can offer insight into the business, such as items browsed, frequent requests, items bought together, etc.

24Integrating Information among Multiple Databases Integration allows separate systems to communicate directly with each otherForward integration takes information entered into a given system and sends it automatically to all downstream systems and processesBackward integration takes information entered into a given system and sends it automatically to all upstream systems and processes

25One of the biggest benefits of integration is that organizations only have to enter information into the systems once and it is automatically sent to all of the other systems throughout the organizationThis feature alone creates huge advantages for organizations because it reduces information redundancy and ensures accuracy and completenessWithout integrations an organization would have to enter information into every single system that requires the information from marketing and sales to billing and customer serviceFor example, customer information would have to be manually entered into the marketing, sales, ordering, inventory, billing, and shipping databases. (Each of these systems are separate and would have their own database if the company doesnt have a complete ERP installed.) Entering the same customer information into multiple systems is redundant, and chances of making a mistake in one of the systems is highIntegrations offer many advantages, but for the most part, the automated flow of information among separate systems is the biggest benefit

Integrating Information among Multiple Databases Forward integration

26Identify the arrows along the top of the figure when explaining forward integrationsBasically, all information flows forward along the business processSales enters the information when it is negotiating the sale (looking for opportunities)The information is then passed to the order entry system when the order is actually placedThe order fulfillment system picks the products from the warehouse, packs the products, labels boxes, etcOnce the order is filled and shipped, the customer is billedWhat would happen if users could enter order information directly into the billing system?The systems would quickly become out-of-sync. There might be bills for nonexistent orders, or orders that do not have any bills (if someone deleted a bill) For this reason organizations typically place a business-critical integrity constraint on integrated systems: With a forward integration the information must be entered in the sales system, you could not enter information directly into the billing systemIntegrations are expensive to build and maintainIntegrations are difficult to implementFor these reasons many organizations only build forward integrations and use business-critical integrity constraints to ensure all information is always entered only at the start of the integration (one source of record)

Integrating Information among Multiple Databases Backward integration

27Identify the arrows along the bottom of the figure when explaining backward integrationsBasically, all information flows backward along the business processBilling enters information and this information is passed back to the order systemThe order fulfillment system passes the information back to the order entry systemThe order entry system passes the information back to the sales systemWhy would an organization want to build both forward and backward integrations?This allows users to enter information at any point in the business process and the information is automatically sent upstream and downstream to all other systemsFor example, if order fulfillment determined that they could not fulfill an order (the product had been discontinued), they could simply enter this information into the database and it would be sent automatically upstream to the sales representative who could contact the customer and downstream to billing to remove the item from the billIntegrating Information among Multiple Databases Building a central repository specifically for integrated information

28The above figure displays an example of customer information integrated using this methodUsers can create, read, update, and delete in the main customer repository, and it is automatically sent to all of the other databasesThis method does not follow the business process when building the integrationsBusiness-critical integrity constraints still need to be built to ensure information is only ever entered into the customer repository, otherwise the information will become out-of-sync

Without integration, an organization will: Spend considerable time entering the same info in multiple system Suffer from the low quality and inconsistency typically embedded in redundant info.