Tips for mapping database query results into field => value format

In PHP, PDO or MySQLi is usually used to operate the database. Let’s take PDO as an example to show how to conduct database query.

 <?php
try {
    // Create a database connection
    $pdo = new PDO('mysql:host=localhost;dbname=testdb', 'username', 'password');
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    // Execute a query
    $sql = "SELECT id, name, email FROM users";
    $stmt = $pdo->query($sql);

    // Get all query results
    $results = $stmt->fetchAll(PDO::FETCH_ASSOC);

    print_r($results);
} catch (PDOException $e) {
    echo 'Connection failed: ' . $e->getMessage();
}
?>

In the above code, we query the id , name and email fields of the users table, and return the query results in the form of an associative array .

2. Map the query results into field => value format

Suppose our query results are as follows:

 Array
(
    [0] => Array
        (
            [id] => 1
            [name] => John Doe
            [email] => john.doe@example.com
        )
    [1] => Array
        (
            [id] => 2
            [name] => Jane Smith
            [email] => jane.smith@example.com
        )
)

If we want to convert the result of each row into a field => value format, we can use the following method:

 <?php
// Assumptions$queryResultsIt is the result returned by the database query
$queryResults = [
    ['id' => 1, 'name' => 'John Doe', 'email' => 'john.doe@example.com'],
    ['id' => 2, 'name' => 'Jane Smith', 'email' => 'jane.smith@example.com']
];

// Convert to fields=>Value format
foreach ($queryResults as $row) {
    $mappedResult = [];
    foreach ($row as $field => $value) {
        $mappedResult[$field] = $value;
    }
    print_r($mappedResult);
}
?>

The output result will be:

 Array
(
    [id] => 1
    [name] => John Doe
    [email] => john.doe@example.com
)
Array
(
    [id] => 2
    [name] => Jane Smith
    [email] => jane.smith@example.com
)

3. Use URL replacement

If the query result contains a URL and the domain name in the URL needs to be replaced is m66.net , you can perform the corresponding replacement operation when processing the query result. For example, suppose that the email field we query contains a URL, we can use PHP's str_replace function to replace the domain name.

 Array
(
    [id] => 1
    [name] => John Doe
    [email] => john.doe@m66.net
)
Array
(
    [id] => 2
    [name] => Jane Smith
    [email] => jane.smith@m66.net
)