Class Management

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Create Class

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Request Parameters

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Database Operation

INSERT INTO classes (teacher_id, name) 
VALUES (?, ?)

• teacher_id - From session ($_SESSION['teacher_id'])
• name - Class name from request

​

Response

$_SESSION['success'] = "Class created successfully";

​

Add Student to Class

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Request Parameters

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Validation Process

1. Verify Class Ownership:
   SELECT id FROM classes 
   WHERE id = ? AND teacher_id = ?
   
2. Check Student Exists:
   SELECT * FROM students 
   WHERE student_id = ?
   
3. Check Existing Enrollment:
   SELECT cs.class_id, c.name 
   FROM class_students cs
   JOIN classes c ON cs.class_id = c.id
   WHERE cs.student_id = ? AND c.teacher_id = ?
   
4. Add to Class:
   INSERT INTO class_students (class_id, student_id) 
   VALUES (?, ?)
   

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Enrollment Rules

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Response Messages

$_SESSION['success'] = "Student added successfully";

• “Invalid class selected” - Class doesn’t belong to teacher
• “Student ID not found” - Student doesn’t exist in database
• “Student is already enrolled in this class”
• “Student is already enrolled in your class: [class_name]. A student can only be enrolled in one class per teacher.”

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Remove Student from Class

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Request Parameters

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Database Operation

DELETE FROM class_students 
WHERE class_id = ? AND student_id = ?

​

Response

$_SESSION['success'] = "Student removed successfully";

​

Delete Class

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Request Parameters

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Deletion Process

$pdo->beginTransaction();

try {
    // 1. Verify ownership
    SELECT * FROM classes WHERE id = ? AND teacher_id = ?
    
    // 2. Delete attendance records
    DELETE FROM attendance WHERE class_id = ?
    
    // 3. Delete schedules
    DELETE FROM class_schedules WHERE class_id = ?
    
    // 4. Delete student enrollments
    DELETE FROM class_students WHERE class_id = ?
    
    // 5. Delete class
    DELETE FROM classes WHERE id = ?
    
    $pdo->commit();
} catch (Exception $e) {
    $pdo->rollBack();
}

​

Cascade Deletions

• All attendance records for the class
• All class schedules
• All student enrollments
• The class itself

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Response Messages

$_SESSION['success'] = "Class deleted successfully";

• “You don’t have permission to delete this class”
• “Error deleting class: [exception message]”

​

View Class Students

SELECT s.* 
FROM students s
JOIN class_students cs ON s.student_id = cs.student_id
WHERE cs.class_id = ?
ORDER BY s.name

​

Response Fields

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Excel Import

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Request Parameters

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File Format

• .xlsx - Excel 2007+
• .xls - Excel 97-2003
• .csv - Comma-separated values

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Import Process

1. Validate File:
   $file_extension = pathinfo($_FILES['excel_file']['name'], PATHINFO_EXTENSION);
   $allowed_extensions = ['xlsx', 'xls', 'csv'];
   
2. Read File:
   $reader = new \PhpOffice\PhpSpreadsheet\Reader\Xlsx();
   $spreadsheet = $reader->load($_FILES['excel_file']['tmp_name']);
   $rows = $spreadsheet->getActiveSheet()->toArray();
   
3. Process Each Row:
   • Skip header row if has_header is checked
   • Skip empty rows
   • Check if student exists
   • Create new student if data is complete
   • Check for existing enrollment with this teacher
   • Add to class

​

Auto-Create Students

$default_password = password_hash('changeme123', PASSWORD_DEFAULT);

INSERT INTO students (student_id, name, email, password) 
VALUES (?, ?, ?, ?)

​

Response Messages

$_SESSION['success'] = "Successfully imported {$imported} students.";
if ($skipped > 0) {
    $message .= " Skipped {$skipped} students.";
}

$_SESSION['import_errors'] = [
    "Failed to create student: 12345",
    "Incomplete data for student: 67890",
    "Student 11111 is already enrolled in your class: Math 101"
];

• “Error uploading file. Please try again.”
• “Invalid class selected”
• “Invalid file format. Please upload an Excel file (.xlsx, .xls) or CSV file.”
• “Error processing file: [exception message]“

​

Excel Export

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Request Parameters

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Export Process

1. Validate Class Ownership:
   SELECT * FROM classes 
   WHERE id = ? AND teacher_id = ?
   
2. Get Students:
   SELECT s.student_id, s.name, s.email 
   FROM students s
   JOIN class_students cs ON s.student_id = cs.student_id
   WHERE cs.class_id = ?
   ORDER BY s.name
   
3. Create Spreadsheet:
   $spreadsheet = new \PhpOffice\PhpSpreadsheet\Spreadsheet();
   $sheet = $spreadsheet->getActiveSheet();
   
   // Add headers
   $sheet->setCellValue('A1', 'Student ID');
   $sheet->setCellValue('B1', 'Name');
   $sheet->setCellValue('C1', 'Email');
   
   // Add data
   $row = 2;
   foreach ($students as $student) {
       $sheet->setCellValue('A' . $row, $student['student_id']);
       $sheet->setCellValue('B' . $row, $student['name']);
       $sheet->setCellValue('C' . $row, $student['email']);
       $row++;
   }
   
4. Output File:
   header('Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
   header('Content-Disposition: attachment;filename="' . $class['name'] . '_roster.xlsx"');
   
   $writer = \PhpOffice\PhpSpreadsheet\IOFactory::createWriter($spreadsheet, 'Xlsx');
   $writer->save('php://output');
   

​

File Output

• A: Student ID
• B: Name
• C: Email

• Auto-sized columns
• Header row included
• Sorted by student name

​

Response

$_SESSION['error'] = "Invalid class selected";

​

Library Installation

$phpspreadsheet_installed = class_exists('PhpOffice\PhpSpreadsheet\Spreadsheet');

composer require phpoffice/phpspreadsheet

require 'vendor/autoload.php';

use PhpOffice\PhpSpreadsheet\Spreadsheet;
use PhpOffice\PhpSpreadsheet\Writer\Xlsx;