PHP and MySQL
PHP is commonly used with MySQL to perform database operations. In order to perform database operations in PHP, you need to connect to the database first. Once you have established a connection, you can perform CRUD (Create, Read, Update, and Delete) operations on the database. Here's how you can connect to a MySQL database and perform CRUD operations in PHP:
Connecting to a MySQL Database
To connect to a MySQL database in PHP, you can use the mysqli_connect() function. Here's an example:
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "example";
$conn = mysqli_connect($servername, $username, $password, $dbname);
if (!$conn) {
die("Connection failed: " . mysqli_connect_error());
}
In this example, we first define the server name, username, password, and database name. We then use the mysqli_connect() function to establish a connection to the database. If the connection fails, we output an error message using the mysqli_connect_error() function.
Performing CRUD Operations
Once you have established a connection to the database, you can perform CRUD operations. Here are some examples:
Creating Records
To create a record in a MySQL database, you can use the mysqli_query() function to execute an SQL INSERT statement. Here's an example:
$sql = "INSERT INTO users (name, email, password) VALUES ('John Doe', 'johndoe@example.com', 'password123')";
if (mysqli_query($conn, $sql)) {
echo "Record created successfully";
} else {
echo "Error: " . mysqli_error($conn);
}
In this example, we use the mysqli_query() function to execute an SQL INSERT statement that creates a new record in the users table.
Reading Records
To read records from a MySQL database, you can use the mysqli_query() function to execute an SQL SELECT statement. Here's an example:
$sql = "SELECT * FROM users";
$result = mysqli_query($conn, $sql);
if (mysqli_num_rows($result) > 0) {
while ($row = mysqli_fetch_assoc($result)) {
echo "Name: " . $row["name"] . " - Email: " . $row["email"] . "<br>";
}
} else {
echo "0 results";
}
In this example, we use the mysqli_query() function to execute an SQL SELECT statement that retrieves all records from the users table. We then use a while loop to iterate through the results and output the name and email of each user.
Updating Records
To update a record in a MySQL database, you can use the mysqli_query() function to execute an SQL UPDATE statement. Here's an example:
$sql = "UPDATE users SET name='Jane Doe' WHERE id=1";
if (mysqli_query($conn, $sql)) {
echo "Record updated successfully";
} else {
echo "Error: " . mysqli_error($conn);
}
In this example, we use the mysqli_query() function to execute an SQL UPDATE statement that updates the name of the user with an ID of 1.
Deleting Records
To delete a record from a MySQL database, you can use the mysqli_query() function to execute an SQL DELETE statement. Here's an example:
$sql = "DELETE FROM users WHERE id=1";
if (mysqli_query($conn, $sql)) {
echo "Record deleted successfully";
} else {
echo "Error: " . mysqli_error($conn);
}
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In this example, we use the mysqli_query() function to execute an SQL DELETE statement that deletes the user with an ID of 1 from the users table.
Closing the Connection
After you have finished performing database operations, it's important to close the connection to the database using the mysqli_close() function. Here's an example:
mysqli_close($conn);
In this example, we use the mysqli_close() function to close the connection to the database.
Summary
To summarize, PHP can be used with MySQL to perform CRUD operations on a database. To perform these operations, you need to first establish a connection to the database using the mysqli_connect() function. You can then use various functions, such as mysqli_query(), to execute SQL statements to perform CRUD operations on the database. Finally, it's important to close the connection to the database using the mysqli_close() function when you're finished with your database operations.
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