the online grade book

The Online Grade BookThe Online Grade Book

Charles R. Moen, M.S.Morris M. Liaw, Ph.D.

October 18, 2003

A Case Study in Learning About Object-Oriented Database TechnologyA Case Study in Learning About Object-Oriented Database Technology

ACET 2003ACET 2003

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Why do we need OODB?Why do we need OODB?

1. When creating an application with an object-oriented programming language…

• Objects can be saved without translating them to another data structure

• Vice versa, stored objects can be loaded without translation

• Efficiency and speed!

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Why do we need OODB?Why do we need OODB?

2. When creating an application that uses complex data, e.g., building a space shuttle, creating an electronic medical record system, storing bioinformatics sequence information,…• Complex data can be stored without

complicated table schemas

• Data can be retrieved by pointer traversal, no need for time-consuming joins

• Efficiency, speed, and complexity!

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Background HighlightsBackground Highlights

Object-oriented database• Persistent store of objects created with an OO

programming language

Advantages• No need to convert objects to tables• Capable of storing entities with complex relationships • Faster—no need for joins

Some important points• No tables, no need for normalization• Capable of computing transitive closure• Relational databases are better for business apps

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How do we teach OODB?How do we teach OODB?

CSCI 5433 Object-Oriented Database Systems• Prerequisites

- CSCI 3233 Object-Oriented Design and Programming (C++)- CSCI 5333 Database Management Systems (DB theory)

• Learning Goals- Learn how to use OOAD for database development- Learn how to use OO technology to develop an OO

database and a Web application that uses it as a backend

• Tools- Object Modeling Technique (OMT)- ObjectStore and MS Visual C++

• Project- The Online Grade Book

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ResourcesResources

1.TextbookObject-Oriented Modeling and Design

for Database ApplicationsMichael Blaha & William PremerlaniPrentice-Hall, 1998

ISBN 0-13-123829-9

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Resources (Cont.)Resources (Cont.)

2.Software• ObjectStore

- OO database management software- Progress Software Corporation

- http://www.progress.com/- http://www.objectstore.net/index.ssp

- Educational license available

• MS Visual C++- ObjectStore Wizards create C++ code- Writing the callbacks- Compiling the DLLs

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3.ObjectStore Manuals• Extensive PDF documentation

• The most important manuals- Rapid Database Development

- ObjectForms Publisher Tutorial

- Inspector Tutorial

- ObjectForms User Guide

- C++ API User Guide

- Building C++ Interface Applications

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4. Computer Lab• Dedicated room with seven PCs

• PC configuration

- Windows 2000

- ObjectStore

- MS Visual C++

• ObjectStore Mini Server

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Teaching TechniqueTeaching Technique

Lecture• Intro to OODB

Student presentations• Based on textbook and ObjectStore manuals

Project assignment• Online Grade Book• Personal home page with links to the project

Exams• Midterm and final

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Learning GoalsLearning Goals

1. Learn how to use OOAD for database development

• OMT Methodology

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OMT MethodologyOMT Methodology

Object Modeling Technique (OMT)

Developed by James Rumbaugh

Consists of:• Concepts about object modeling• A process called the “OMT Process”• Modeling notation

Learning Goal 1 – Learning How to Use OOADLearning Goal 1 – Learning How to Use OOADLearning Goal 1 – Learning How to Use OOADLearning Goal 1 – Learning How to Use OOAD

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The OMT ProcessThe OMT Process

1. Conceptualization

2. Analysis

3. System design

4. Detailed design

5. Implementation

6. Maintenance

Learning Goal 1 – Learning How to Use OOADLearning Goal 1 – Learning How to Use OOADLearning Goal 1 – Learning How to Use OOADLearning Goal 1 – Learning How to Use OOAD

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Learning GoalsLearning Goals

1. Learn how to use OOAD for database development

• OMT Methodology

2. Learn how to use OO technology to develop an OO database and a Web application that uses it as a backend

• Project assignment—“Online Grade Book”

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Learning Goal 2 – Developing an OODBLearning Goal 2 – Developing an OODBLearning Goal 2 – Developing an OODBLearning Goal 2 – Developing an OODB

Project AssignmentProject Assignment

Create an Online Grade Book• Web site where students can check grades• The teacher will record the grades in an OODB• Course grade calculated automatically, according to

weight percentages assigned by the teacher

OMT Process• Conceptualization Report• Analysis Report• Project Report

Implementation• ObjectStore and C++• Final Demonstration

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OMT Process StepsOMT Process Steps

1. Conceptualization• Business analysts or users conceive of

an application and list requirements

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Step 1, ConceptualizationStep 1, Conceptualization

Why is the Online Grade Book needed?• Students can get grades without contacting the teacher• Teacher will not have to contact each individual student

What problems will it solve?• Problem statement: Develop software for an online grade book

using ObjectStore. The following capabilities must be provided:- Provide an automated system to show students their grades

- Allow the student to see his grades after entering his ID

- Display all the grades for that student, including the midterm exam grade, the final exam grade, the presentation grade, the group project grade, the individual project grade, the course score, and the course letter grade.

- Permit the teacher to change all the student data, including the name, password, and grades

- Permit the teacher to change the grade weights for the grade components

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What problems will it solve? (Cont.)• Detailed software requirements: (examples)

- The system shall have an ID for each user.- The ID shall be an integer assigned to each student in a class by the

teacher.- The system shall provide a course ID for each user.- The course ID shall identify the specific course that the student is

enrolled in, including the course number, section, semester, and year.- The system shall check the ID of the user when he wants to check his

grades.- The system shall identify whether a user is a student or an administrator.

Where will it be used?• Environment—UHCL campus• System requirements

When is it needed?—The end of the semester


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Who is the application for?• Actors

AdministratorStudent

Edit Grade Weights

View Grades

Edit Student Data

How will it work?• Scenarios and use cases

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1 WHO IS THE APPLICATION FOR?1.1 USERS

1.1.1 Student—Description, Responsibilities, Success Criteria1.1.2 Administrator —Description, Responsibilities, Success Criteria

2 WHAT PROBLEMS WILL IT SOLVE?2.1 APPLICATION OVERVIEW2.2 PROBLEM STATEMENT2.3 DETAILED SOFTWARE REQUIREMENTS

3 WHERE WILL IT BE USED?3.1 ENVIRONMENT (e.g., UHCL classrooms)3.2 SYSTEM REQUIREMENTS

3.2.1 Server Software (e.g., MS IIS, ObjectStore)3.2.1 Client Software (e.g., modern Web browser)3.2.2 Development Software (e.g., ObjectStore, MS Visual C++, Notepad)

4 WHEN IS IT NEEDED?4.1 PROJECT DEADLINE

Conceptualization Report

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5 WHY IS IT NEEDED?5.1 CONTEXT (e.g., class assignment)5.2 OBJECTIVES

6 HOW WILL IT WORK?6.1 SCENARIOS

6.1.1 Initial setup and addition of students by the Administrator6.1.2 Adding the grades6.1.3 Checking the grades

6.2 USE CASES6.2.1 Use case diagram6.2.2 Use case descriptions

6.2.2.1 View grades—preconditions, flow, post conditions6.2.2.2 Edit student data —preconditions, flow, post conditions6.2.2.3 Edit grade weights —preconditions, flow, post conditions

6.3 INITIAL ARCHITECTURE

Conceptualization Report (Cont.)

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2. Analysis• Real-world models are constructed• Specify what to do, not how to do it

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Step 2, AnalysisStep 2, Analysis

Attribute-based approach (not OO)• Used with relational databases• List attributes in related groups• Check normal forms

Course( courseID, courseName, teacherName, departmentName)

Course( courseID, courseName, teacherID , departmentID )

Teacher( teacherID, teacherName )

Department( departmentID, departmentName )

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Entity-based approach (OO technique)• Real-world entities and relationships

between them• Advantages:

- Fewer entities than attributes- No need to check normal forms- Compatible with OO program code

Course

courseIDcourseName

Teacher

teacherName

Department

departmentNameteaches taught in

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Object Model(Defines

the structure,e.g., classes)Dynamic Model

(State Diagram,but not used for databases)

Functional Model(Defines operations of objects)

OMT Methodology Models

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Step 2, AnalysisStep 2, AnalysisStep 2, AnalysisStep 2, AnalysisLearning Goal 2 – Developing an OODBLearning Goal 2 – Developing an OODBLearning Goal 2 – Developing an OODBLearning Goal 2 – Developing an OODB

• Develop software for an online grade book using ObjectStore. The following capabilities must be provided:

- Provide an automated system to show students their grades





Object ModelObject Model

Start with the problem statement

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Start with the problem statement Locate nouns to find the entities for classes

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Object ModelObject Model Eliminate unnecessary classes that are:• Irrelevant: software, book, capabilities, system• Redundant: data, components• Used only as values (attributes): grades, score, ID, name, password

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Teacher


WeightStudent

Establish the model’s basic structure

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Object ModelObject Model List the attributes

Weight

midtermWeight: floatfinalWeight: floatpresentationWeight: floatgroupProjectWeight: floatindividualProjectWeight: floatcourseID: char[10]

TeacherStudent

fName: char[50]mName: char[50]lName: char[50]midterm: floatfinal: floatpresentation: floatgroupProject: floatindividualProject: floatcourseScore: floatcourseGrade: char[10]

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Object ModelObject Model Add associations and refine the model

Weight


TeacherStudent

fName: char[50]mName: char[50]lName: char[50]midterm: floatfinal: floatpresentation: floatgroupProject: floatindividualProject: floatcourseScore: floatcourseGrade: char[10]weightTable: os_Collection<Weights *>

Person

userID: char[10] password: char[10]

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Object Model NotationObject Model NotationClass

Association

Multiplicity

Inheritance

Attributes

Weight


TeacherStudent


Person

userID: char[10] password: char[10]

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Functional ModelFunctional Model

Start with the use cases1. View grades2. Edit student data (includes adding grades)3. Edit grade weights

Straightforward object creation, deletion, or retrieval? attribute value update?—no need for pseudocode

Use case 2 requires pseudocode for the course grade, since it is calculated

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Functional ModelFunctional ModelUse Case 2: This is the pseudocode for setting the course score and the course grade for a student. They must be calculated, and the calculations are triggered when the administrator sets the student’s final exam score.

Student::setFinal ( finalGrade )self.final := finalGrade;self#setCourseScore( );return;

Student::setCourseScore ( )score := 0;score += self.midterm * self.weightTable.midtermWeight;score += self.final * self.weightTable.finalWeight;score += self.presentation * self.weightTable.presentationWeight;score += self.groupProject * self.weightTable.groupProjectWeight;score += self.individualProject * self.weightTable.individualProjectWeight;self.courseScore := score;self#setCourseGrade( );return;

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Functional ModelFunctional Model(Use Case 2 cont.)

Student::setCourseGrade ( )if self.courseScore >= 93 then self.courseGrade := “A”;else if self.courseScore >= 90 then self.courseGrade := “A-”;else if self.courseScore >= 87 then self.courseGrade := “B+”;else if self.courseScore >= 83 then self.courseGrade := “B”;else if self.courseScore >= 80 then self.courseGrade := “B-”;else if self.courseScore >= 77 then self.courseGrade := “C+”;else if self.courseScore >= 73 then self.courseGrade := “C”;else if self.courseScore >= 70 then self.courseGrade := “C-”;else self.courseGrade := “F”;end ifreturn;

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Navigational FlowNavigational Flow

All pages in the Web site

Block diagram—each page is a rectangle with a descriptive name

All links between the pages drawn as directional lines

Initial design of each page usually developed at the same time

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Navigational FlowNavigational Flow

Change

AdminChange Dialog OK or Cancel

Logout

AdminAdd Student Dialog

AdminGrade Weight Dialog

Add A New Student Edit Grade Weights

Admin Log InAdministrator Log In

Admin?

OK

Y

N

AdminGrade Report

Delete

Enter Student ID

Found?

StudentGrade Report

OK

Y

N

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Web Page LayoutsWeb Page Layouts

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Analysis Report1 NAVIGATIONAL FLOW BETWEEN WEB PAGES

2 WEB I/O COMPONENTSA list of the forms, buttons, and links for each Web page

3 WEB PAGE LAYOUTSThe design of each Web page in the navigational flow chart

4 ANALYSIS OBJECT MODEL

5 ANALYSIS FUNCTIONAL MODEL

5.1 USE CASES (a list of the use cases)

5.2 PSEUDOCODE

6 DATA DICTIONARY

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2. Analysis• Real-world models are constructed• Specify what to do, not how to do it

3. System Design• Develop the high-level architecture

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Created bythe developer

Step 3, System DesignStep 3, System Design

HTTP

:oodb server:personal computer

ObjectStoreApplicationPackages

Web ServerClient

Browser

*.DLL

TemplateFiles

*.OFT *.DB

CallbackFunctions

(e.g., the WebConnect CGI programand the Template Processor)

PersistentObjects

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OMT Process Steps (Cont.)OMT Process Steps (Cont.)

4. Detailed Design• Adjustments to simplify implementation

and improve execution

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Step 4, Detailed DesignStep 4, Detailed Design

Simplify the object model

Weight

courseID: char[10]midtermWeight: floatfinalWeight: floatpresentationWeight: floatgroupProjectWeight: floatindividualProjectWeight: float

Teacher

Person

userID: char[10]password: char[10]

Student


Analysis Object Model Detailed Design Object Model

Weight

midtermWeight: char[50]finalWeight: char[50]presentationWeight: char[50]groupProjectWeight: char[50]individualProjectWeight: char[50]courseID: char[50]

Person

userID: char[50]password: char[50]fName: char[50]mName: char[50]lName: char[50]midterm: char[50]final: char[50]presentation: char[50]groupProject: char[50]individualProject: char[50]courseScore: char[50]courseGrade: char[10]courseID: char[50]admin: char[10]

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Step 4, Detailed DesignStep 4, Detailed DesignStep 4, Detailed DesignStep 4, Detailed DesignLearning Goal 2 – Developing an OODBLearning Goal 2 – Developing an OODBLearning Goal 2 – Developing an OODBLearning Goal 2 – Developing an OODB

Database DesignerDatabase Designer GUI-based ObjectStore program Used to draw the “Detailed Design” object model Saves the database schema in a *.dbs file

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Database DesignerDatabase Designer Create the classes and save as gradebook.dbs

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OMT Process Steps (Cont.)OMT Process Steps (Cont.)

4. Detailed Design• Adjustments to simplify implementation

and improve execution

5. Implementation• Translate the design into code

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Step 5, ImplementationStep 5, Implementation

ObjectStore tools for implementation• Visual C++ Wizards (e.g., Component Wizard)• Inspector• Publisher• Mini Server

MS Visual C++• Run the ObjectStore Wizards• Write the methods from the functional model• Write the callback functions for adding,

deleting, and editing items in the database

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Step 5, ImplementationStep 5, ImplementationStep 5, ImplementationStep 5, ImplementationLearning Goal 2 – Developing an OODBLearning Goal 2 – Developing an OODBLearning Goal 2 – Developing an OODBLearning Goal 2 – Developing an OODB

Component WizardComponent Wizard

Automatically writes code for all classes created by Database Designer• Including “get” and “set” methods• Inserts “TODO” comments as placeholders

for recommended modifications• Creates main( ), which can be modified to

create and populate the OODB file

When these files are compiled the DLL is created

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Component WizardComponent Wizard Begin by starting MS Visual C++ In the File menu, select New In Projects, select “ObjectStore Component Wizard”

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Component WizardComponent Wizard In the Wizard, open the gradebook.dbs created by

Database Designer Then skip to the third Wizard screen, and select

“Console Application”

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Component WizardComponent Wizard After clicking “Finish,” a complete ObjectStore project

will be created, including these files:• Weight.h, Weight.cpp, Person.h, and Person.cpp

- Attributes- Constructors- “set” and “get” methods

• gradebook.def—DLL definition file• gradebook.dsp—DLL project file• gradebook.dsw—workspace file• schema.scm—schema definition used by automatic processes

A Console project will also be created, including:• main.cpp —will create the database file when executed

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Visual C++Visual C++ Write the “special” methods

• Any methods other than routine “set” and “get” methods• Methods that are specified in the functional model• Example: Setting the course grade

void Student::set_CourseGrade(char *value){if(value) {

int len = strlen(value);if(len < 10)

strcpy(CourseGrade, value);else {

strncpy(CourseGrade, value, 9);CourseGrade[9]=0;

}}else

CourseGrade[0]=0;}

Generated by the Wizard:void set_CourseGrade(double score) {

if( score >= 93.0 ) {strcpy(CourseGrade, "A");

}else if( score >= 90.0 ){

strcpy(CourseGrade, "A-");}

/* … */else {

strcpy(CourseGrade, "F");}

};

Added by the developer:

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Visual C++Visual C++ Create the DLL—Compile the ObjectStore project

(gradebook) that has the Person and Weight classes Create the gradebook.db file to hold the database

• In the Console project (gradebook_console), modify main.cpp

• Compile and execute the Console project

//os_database * db = os_database::open("", 0, 0666);//db->close( );

os_database * db = os_database::open(“gradebook.db", 0, 0666);db->close( );

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OS_BEGIN_TXN (tx_transaction_number_0, 0, os_transaction::update)

OS_END_TXN(tx_transaction_number_0)

Weight *aNewWeight = new(db,Weight_type) Weight(25, 25, 15, 15, 20, "2002fa5433");WeightColl->insert(aNewWeight);

os_collection* WeightColl = (os_collection*)WeightRoot->get_value();if(!WeightColl) {

WeightColl = &os_collection::create(db);WeightRoot->set_value(WeightColl);

}

os_database_root *WeightRoot = db->find_root("Weight_root");if(!WeightRoot) {

WeightRoot = db->create_root("Weight_root");}

Visual C++Visual C++ If desired, additional code can be added to main.cpp to

populate the gradebook.db file with some objects

Recompile and execute the Console project

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Visual C++Visual C++ To update the database content dynamically within the

Web application• The developer must write the C++ code that will make updates

• Callback functions- addItem.cpp- deleteItem.cpp- editItem.cpp

• Added to the DLL when compiled

• “ObjectForms AppWizard” generates a skeleton C++ source file that can be modified

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Visual C++ CallbacksVisual C++ Callbacks In the File menu, select New In Projects, select “ObjectForms AppWizard”

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Visual C++ CallbacksVisual C++ Callbacks Select “Publisher callback DLL” Enter “3” because we need three callback functions (for

adding, deleting, and editing) Use meaningful names (e.g., addItem, deleteItem)

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Visual C++ CallbacksVisual C++ Callbacks Edit the skeleton callbacks in Visual C++

os_database* theDB = SyncOpenWriteDB(dbName, b_wasOpenMVCC);bError = (theDB == NULL);if(!bError) {

TIX_HANDLE(err_objectstore) {OS_BEGIN_TXN(AddItem_txn, 0, os_transaction::update) {

/************************************************** * TODO: Add transaction code *************************************************/}

OS_END_TXN(AddItem_txn);}

TIX_EXCEPTION {bError=TRUE;/****************************************************** * TODO: Add exception handling code *****************************************************/

} TIX_END_HANDLE;

}SyncCloseWriteDB(theDB, b_wasOpenMVCC);

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Visual C++ CallbacksVisual C++ Callbacks // TODO: Add transaction code

//Get the person root and the person collectionos_database_root *PersonRoot = theDB->find_root("Person_root");if(! PersonRoot) {

bError = TRUE;sprintf(errorStr,"<p>Error looking for root.</p>");

}else {

os_collection* PersonColl = (os_collection*) PersonRoot->get_value();if( ! PersonColl ) {

bError = TRUE;sprintf(errorStr,"<p>Error looking for root value.</p>");

}else {

//Create a new student from the dataPerson *newPerson =

new(theDB,&Person_type) Person(courseid,studentid,lname,fname,mname,admin,coursegrade,midterm,final,presentation,groupproject,individualproject, coursescore,midtermaverage,finalaverage,presenterid,atoi(baddtoroot));

//Insert the new person into the collectionPersonColl->insert(newPerson);

}}

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OFT TemplatesOFT Templates

Create the Web pages

HTML with special ObjectForms tags• Server-side code that generates HTML• Used to publish OODB data on a Web page

Created by ObjectForms Publisher

OFT files can be modified• Any text editor• Add formatting to change the page appearance• Refine the code by adding ObjectForms tags

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PublisherPublisher

Uses gradebook.db to publish data on the Web page

Creates the *.oft template files in the Publish Wizard

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<%include "Headers\GradeBookHeader.html"%><%osdatabase=“C:\gradebook\gradebook_console\gradebook.db"%><%QUERY NAME="query1" OSFUNCTION="osiquery"%><%if query1.Status EQ 0%><TABLE BORDER=0 CELLPADDING=7 CELLSPACING=0 width="745"><%BEGINDETAIL NAME="query1"%>

<TR><TD ALIGN="left" BGCOLOR=#FFFFFF><%CourseID%></TD><TD ALIGN="center" BGCOLOR=#FFFFFF><%MidTermWeight%> %</TD><TD ALIGN="center" BGCOLOR=#FFFFFF><%FinalWeight%> %</TD><TD ALIGN="center" BGCOLOR=#FFFFFF><%PresentationWeight%> %</TD><TD ALIGN="center" BGCOLOR=#FFFFFF><%GroupProjectWeight%> %</TD><TD ALIGN="center" BGCOLOR=#FFFFFF><%IndividualProjectWeight%> %</TD></TR>

<%ENDDETAIL%></TABLE><%else%><%query1.ErrorMsg%><p><%endif%></body></html>

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Local TestingLocal Testing Publisher Runtime Service

• An ObjectForms service that provides the callback functions• Set the configuration by adding gradebook.DLL• Start the service—runs in a separate console window

Start the MiniServer• An ObjectStore HTTP server• Listens on port 8484 by default

Start your browser, and enter the URL for the opening page of the Online Grade Book• http://129.7.166.73:8484/Grades_submit.html

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Implementation StepsImplementation Steps

ObjectStoreComponent Wizard

ObjectStoreComponent Wizard

gradebook Projectgradebook Project

gradebook_consoleProject

gradebook_consoleProject gradebook.dbgradebook.db

gradebook.DLLgradebook.DLL

Creates

When compiled,creates

To create andpopulate initially

The OO database

The classes

1. Implement the classes drawn with Database Designer and create the database.

ObjectFormsAppWizard

ObjectFormsAppWizard

Skeletoncallback functions

Skeletoncallback functions

MS Visual C++MS Visual C++

Creates Callback functionsin DLL

Callback functionsin DLL

Modify and compile

When compiled,creates

To add, delete, oredit the data

2. Create the callback functions.

ObjectFormsPublisher

ObjectFormsPublisher

Queries and initial*.OFT templates

Queries and initial*.OFT templates

Formatted*.OFT templates

Formatted*.OFT templates

Text editorText editor

Modify

CreatesModifications

added

The Web pages

3. Create the Web pages.

4. Test with the MiniServer, then make any necessary revisions.

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Completed ProjectCompleted Project The student ID is used to retrieve the grades

Grades_submit.html

Grades_submit.oft

HTML response displays the grades if the student ID is valid, else an error message says to try again

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Completed ProjectCompleted Project By clicking on “Administrator Login,” the teacher can

go the admin login page

Grades_admin.html

The grades of all students are displayed to the teacher

Grades.oft

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Completed ProjectCompleted Project Clicking on “Add A New Student” lets the teacher enter

student data, which is added after clicking “Add”

Grades_add_user.oft Grades_add_commit_user.oftAdd

Clicking on “Edit” lets the teacher change student data

Grades_edit_user.oft

Grades_edit_commit_user.oftEdit

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Completed ProjectCompleted Project By clicking on “View Grade Weights,” the teacher can

view the weight for calculating the course score

Weights.oft

By clicking on “Edit Grade Weights,” the weights can be changed

Weights_edit_user.oft

Weights_edit_commit.oftEdit

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Step 5, ImplementationStep 5, Implementation

Project Report1 SPECIAL FEATURES

A list of any unique features

2 LESSONS LEARNEDProblems and solutions

3 USER NAMES AND PASSWORDS FOR TESTING

4 USER GUIDE

5 FLOW CHART

The final design of the navigational flow chart

6 CODE FOR TEMPLATES AND C++ CALLBACK FUNCTIONS

7 STEPS FOR DEVELOPING AND DEPLOYING

8 DIARY

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ConclusionConclusion

Students were able to learn OO analysis and design with real-world tools

Students were also able to implement an OO database and use it with a Web application that they developed

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Thank You Thank You

Any questions?

the online grade book

Documents