MySQL与Firebird：使用PDO访问PHP中的查询列

Question

From what I understood, using PDO should be the same result regardless of what DB I am using. I tested this in the following code, which I have connected to two separate DB's.

$sth = $pdo->query('SELECT * FROM posts');
while($result = $sth->fetch(PDO::FETCH_BOTH)){
    echo $result[1] . '<br>';
};

MySQL DB:

$dsn = 'mysql:host=' . $server . ';dbname=' . $dbname;
$pdo = new PDO($dsn, $username, $password);

Firebird DB:

$dsn = "firebird:dbname=" . $server . ":" . $dbname;
$pdo = new PDO($dsn, $username, $password);

The MySQL connection worked fine, while the Firebird connection worked only with numbered Arrays - FETCH_NUM, and FETCH_BOTH when using index positions. Is this how its supposed to be or am I doing something wrong with my Firebird connection? I will need to work with the Firebird DB in the future, so this really frustrates me. Thank you for all comments.

Answer 1

In Firebird, by default, mainly from historical reasons, unless you use double quotes on object names (field names, tables, etc...), they are uppercase-d and stored internally in uppercase.

Accordingly, the column names you receive in result set are in uppercase, so you should address them in upper-case like $row['FIELD_NAME'] .

Alternatively, in PHP, PDO driver have a special flag used on connection, PDO::ATTR_CASE => PDO::CASE_LOWER/NATURAL/UPPER that adjust the needed case internally for you.

For example:

$source = $d['kind'].':'.'dbname='.$d['host'].':'.$d['base'].';charset='.$d['charset'];
$options = $d['options'] + [
    \PDO::ATTR_CASE => \PDO::CASE_LOWER,
    \PDO::ATTR_DEFAULT_FETCH_MODE => \PDO::FETCH_ASSOC,
    \PDO::ATTR_ERRMODE => \PDO::ERRMODE_EXCEPTION
    ];
$connection = new \PDO($source, $d['user'], $d['password'], $options);

Firebird is not alone doing this. Oracle also stores by default metadata in uppercase. Some DBMSes have options, others in lower-case by default.