# Basic PHP & MySQL CRUD
## **1\. Introduction**
### **What is CRUD?**
CRUD stands for:
* **C**reate – Insert new records
* **R**ead – Fetch and display records
* **U**pdate – Modify existing records
* **D**elete – Remove records
### **Tech Stack**
* PHP
* MySQL (Database)
* Bootstrap (For styling)
## **2\. Setting Up the Database**
### **Create a MySQL Database & Table**
Run this SQL query in phpMyAdmin or MySQL CLI:
```sql
CREATE DATABASE student_db;
USE student_db;
CREATE TABLE student (
id INT AUTO_INCREMENT PRIMARY KEY,
name VARCHAR(100),
email VARCHAR(100),
phone VARCHAR(20)
);
```
## **3\. Connect PHP to MySQL**
### **config.php**
Create a `config.php` file to connect PHP with MySQL:
```php
```
### Explanation of the above code:
1. **Database Credentials**
* `$host = "`[`localhost`](http://localhost)`";` → The database server is running locally.
* `$username = "root";` → The default MySQL username.
* `$password = "";` → No password set for local MySQL (change for production).
* `$db = "student_db";` → The name of the database to connect to.
2. **Connecting to MySQL**
* `mysqli_connect($host, $username, $password, $db);` establishes a connection to MySQL using the provided credentials.
3. **Error Handling**
* `if(!$conn) { die("Connection Error".mysqli_connect_error); }`
* If the connection fails, the script stops and displays an error message.
## **4\. Create (Insert Data)**
### **create.php**
This page will allow users to add new students.
```php
";
// echo "$name";
// echo " ";
// echo "$phone";
$sql = "INSERT INTO student(email,name,phone) values ('$email','$name','$phone')";
$result = mysqli_query($conn,$sql);
if($result){
// echo "Added successfuly.";
echo "
";
// header("location:index.php");
}
else{
echo "Something went wrong.";
}
?>
```
### Explanation of `create.php`
1. **Includes Database Connection**
* `include 'config.php';` connects to the database.
2. **Retrieves Form Data**
* `$email = $_POST['email'];`
* `$name = $_POST['name'];`
* `$phone = $_POST['phone'];`
* Gets user input from the submitted form.
3. **Inserts Data into Database**
* `INSERT INTO student(email, name, phone) VALUES ('$email', '$name', '$phone');`
* Stores the submitted data into the `student` table.
4. **Checks if Data is Inserted Successfully**
* If successful, shows an alert and redirects to `index.php`.
* If failed, displays an error message.
### Purpose
This script handles form submissions and saves user details in the database.
### index.php
```php
Bootstrap demo
```
### Explanation of above script:
1. **HTML Structure**
* Uses `` for an HTML5 document.
* Includes `` for metadata, title, and Bootstrap CDN for styling.
2. **Form Layout**
* Wrapped in a `div` with `width:30%` and centered using `margin:auto;` and `mt-5` for spacing.
* Uses Bootstrap classes for a modern and responsive design.
3. **Form Fields**
* **Email Field:** Uses `type="email"` for validation.
* **Name Field:** Simple text input for user names.
* **Phone Field:** Plain input for entering phone numbers.
* **Checkbox:** Optional selection for additional agreement.
4. **Form Submission**
* The form submits data to `create.php` using `method="post"`, ensuring secure data transfer.
* A **Submit Button** styled with Bootstrap (`btn btn-primary`) sends the form data.
5. **Bootstrap Integration**
* Uses Bootstrap components for styling, including form controls and buttons.
* Bootstrap JavaScript included at the bottom for interactive elements.
## **5\. Read (Display Data)**
### **read.php**
Fetch and display student records in a table.
```php
Bootstrap demo
```
### Explanation of the `read.php` File
1. **Include Database Connection**
* `include 'config.php';` connects to the database.
2. **Fetch Student Data**
* `$_GET['id']` gets the student ID from the URL.
* `SELECT * FROM student WHERE id = $id;` retrieves student details from the database.
* `mysqli_fetch_assoc($result);` stores the student’s details in `$row`.
3. **Display Student Details**
* Uses a Bootstrap `list-group` to show student ID, name, phone, and email.
4. **Return Home Button**
* Provides a button to navigate back to `index.php`.
5. **Bootstrap for Styling**
* Ensures a responsive and visually appealing design.
### Purpose
This page **retrieves and displays a specific student's details** based on their ID, fetched from the database.
## **6\. Update (Edit Data)**
### **update.php**
This page fetches student details and allows editing.
```php
alert('updated successfully');
window.location.href = 'app.php';
";
}
}
?>
Bootstrap demo
```
Here’s a brief explanation of the above code:
1. **Fetching Data**:
* The script gets the student ID from the URL (`$_GET['id']`).
* It queries the database for the student’s details using the ID and stores the result in `$data`.
2. **Form Handling**:
* When the form is submitted via the `POST` method, it updates the student’s details (email, name, phone) in the database using the provided values.
3. **Update Query**:
* The SQL query updates the student’s record in the database with the new details (`$email`, `$name`, `$phone`).
4. **Success Message**:
* If the update is successful, a JavaScript alert is triggered, and the user is redirected to `'app.php'`.
5. **Displaying Data**:
* The existing student details are displayed in the form as default values, allowing the user to edit them.
6. **Bootstrap**:
* The form is styled using Bootstrap for a clean, responsive design. The form includes fields for email, name, phone, and a checkbox.
In short, the code allows editing and updating a student's details in the database using a form interface.
## **7\. Delete (Remove Data)**
### **delete.php**
This script will delete a student record.
```php
alert('Deleted Successfully.');
window.location.href='app.php';
";
}
?>
```
This PHP code performs the following actions:
1. **Connection**: It includes the `config.php` file to establish a connection to the database.
2. **Get the ID**: The `id` of the student to be deleted is retrieved from the URL using `$_GET['id']`.
3. **SQL Query**: It constructs a SQL `DELETE` query to remove the student record from the `student` table where the ID matches the one obtained from the URL.
4. **Execution**: The query is executed using `mysqli_query()`, and the result is stored in the `$result` variable.
5. **Success Check**: If the deletion is successful (i.e., `$result` is truthy), a JavaScript alert displays "Deleted Successfully," and the page is redirected to `'app.php'`.
In short, this script deletes a student record from the database based on the `id` provided in the URL and then alerts the user upon successful deletion.
## 8 . Display
### app.php
This script will display a all student record.
```php
Bootstrap demo
```
### Explanation of `app.php`
1. **Database Connection**
* Includes `config.php` to establish a connection to the MySQL database.
2. **Fetching Data**
* Executes `SELECT * FROM student` to retrieve all student records.
* Uses `mysqli_fetch_all($result, MYSQLI_ASSOC)` to store the result in an associative array.
3. **Displaying Data in a Table**
* Uses Bootstrap to create a responsive table.
* Iterates through student records using `foreach` and displays them in table rows.
4. **Action Buttons**
* Each student row includes:
* **View (**`read.php?id=`) – Displays student details.
* **Edit (**`update.php?id=`) – Allows updating student information.
* **Delete (**`delete.php?id=`) – Removes the student from the database.
5. **Footer**
* Adds a footer with a copyright notice.
6. **Bootstrap Integration**
* Uses Bootstrap for styling and responsiveness.
### **Conclusion**
With this PHP CRUD application, you’ve learned how to:
* Connect to a database.
* Perform basic CRUD operations.
* Use a structured PHP file system.
Feel free to modify and enhance this application for your specific needs!