How to connect to the database with PHP and perform addition, deletion, modification and query

PHP is a widely used server-side scripting language that can be used to easily connect to databases, perform operations such as additions, deletions, modifications, etc. in web development. This article will introduce how to use PHP to connect to the database and perform additions, deletions, modifications and queries.

1. Connect to the database

First, we need to connect to the database. To connect to the database, you need to use the mysql_connect() function provided by PHP. This function requires three parameters, namely the database address, username and password. After the connection is successful, we can start operating the database.

//Connect to the database
$con = mysql_connect("localhost","user","pass");
if (!$con)
{
die('Could not connect: ' . mysql_error());
}

//Select database
mysql_select_db("dbname", $con);
?> ;

2. Insert data

Inserting data requires the mysql_query() function provided by PHP. This function requires passing a SQL statement. The following is an example of inserting data:

// Insert data
mysql_query(
"INSERT INTO users (name, email, password)
VALUES (' John', 'john@example.com', 'password')"
);

// Check whether data is successfully inserted
if (mysql_affected_rows() > 0) {
echo "Success!";
} else {
echo "Fail!";
}
?>

3. Update data

Update data is the same You need to use the mysql_query() function and pass a SQL statement. The following is an example of updating data:

//Update data
mysql_query(
"UPDATE users SET password='new_password'
WHERE email='john@example.com'"
);

// Check whether the data is successfully updated
if (mysql_affected_rows() > 0) {
echo "Success! ";
} else {
echo "Fail!";
}
?>

4. Delete data

Deleting data also requires the use of mysql_query( ) function and pass a SQL statement. The following is an example of deleting data:

// Deleting data
mysql_query("DELETE FROM users WHERE email='john@example.com' ");

// Check whether the data is successfully deleted
if (mysql_affected_rows() > 0) {
echo "Success!";
} else {
echo "Fail !";
}
?>

5. Query data

Querying data also requires using the mysql_query() function and passing a SQL statement. The following is an example of querying data:

// Querying data
$result = mysql_query("SELECT * FROM users WHERE email='john@example.com '");

//Output query results
while ($row = mysql_fetch_array($result)) {
echo $row['name'];
echo $ row['email'];
echo $row['password'];
}
?>

6. Close the connection

When we complete the database After the operation, the connection needs to be closed. The connection can be closed using the mysql_close() function provided by PHP.

//Close the connection
mysql_close($con);
?>

The above is how to use PHP to connect to the database and perform addition, deletion, modification and query Method, I hope it can be helpful to everyone.

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