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PHP and SQL Server: Queries

Steps to Design PHP Pages to Answer User Queries

1. Query generation– What SQL query do we need to retrieve the

desired information?

2. HTML form design– What form element(s) are most suitable for user

input in this case?

3. Query processing and result display– How to query the database and display the results

using PHP?

Example: Case 4

I want a website to show me the information of all projects which

are assigned to one or more specific employees

User input example:1 - Mary Jacobs 5 - Heather Jones

Step 1: Query Generation

• Write SQL query to show the projects which are assigned to employees 1-Mary Jacobs and 5-Heather Jones

Step 1: Query Generation

• Write SQL query to show the projects which are assigned to employees 1-Mary Jacobs and 5-Heather Jones

SELECT * FROM PROJECTWHERE ProjectID IN

(SELECT ProjectIDFROM ASSIGNMENTWHERE EmployeeNumber IN (1,5));

Step 2: HTML Form Design

• Is the following design appropriate?

I want a website to show me the information of all projects which

are assigned to one or more specific employees

Problems: 1. Users may not know which employees are in the database2. Users may not know what information is needed (employee

number, or employee name, or both?)

Step 2: HTML Form Design

• Solution: When possible, give users a list of options to choose from

• Is the following design appropriate?

I want a website to show me the information of all projects which

are assigned to one or more specific employees

Problem: Selection of more than one employee is not allowed.

Step 2: HTML Form Design

• Solution: Using checkboxes• Is the following design

appropriate?

I want a website to show me the information of all projects which

are assigned to one or more specific employees

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Step 2: Code Specificationcase4.php

Retrieve the IDs and names of all employees from database

Use the “while loop” to generate a checkbox for each employee

Name of the array which stores the user’s choices

Value that will be passed to the process page

Value shown on the webpage

Step 3: Query Processing process_case4.php

This is the SQL Query we wrote in Step 1.

Employee numbers are obtained from user input

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Case 4. Try it yourself

• Download the case4.php and process_case4.php from course website.

• Open case4.php and process_case4.php from NotePad++ and add your database information to both files

Input your own information

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Case 4. Try it yourself (cont’d)

Visit the php page to query your database– http://my.up.ist.psu.edu/YourPSUID/case4.php

In-class Exercise: Case 5• Create PHP webpages to show the information of all employees

which are assigned to one or more specific projects– http://my.up.ist.psu.edu/zuz22/case5.php

Step 1: Query Generation

• Write SQL query to show the employees which are assigned to projects with ID 2 and 3.

• Execute the query in SQL Management Studio to make sure you retrieve the desired result

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Step 2: HTML Form Design

• Create case5.php in your webspace, copy from case4.php and modify it

Action to which PHP page?

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Step 2: HTML Form Design (cont’d)

• Modify your case5.phpModify this query to retrieve all projects instead of employees

Modify these lines to display all the projects using checkboxes

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Step 3: Query Processing

• Create process_case5.php, copy from process_case4.php and modify it

What ID should you use now?

Put the SQL Query you wrote in Step 1 here.

The IDs are obtained from user input.