Pdo\Sqlite::createCollation

    (PHP 8 >= 8.4.0)

    Pdo\Sqlite::createCollation — Registers a user-defined function for use as a collating function in SQL statements

    Descrizione

    public Pdo\Sqlite::createCollation(string $name, callable $callback): bool

    This method is similar to Pdo\Sqlite::createFunction() except that it registers functions that are used to collate strings.

    Elenco dei parametri

    name
    Name of the SQL collating function to be created or redefined.
    callback
    Callback function that defines the behaviour of a collation. It must accept two strings and return -1, 0, or 1 if the first string sorts before, sorts identically, or sorts after the second string respectively. An internal function that behaves like this is strcmp().

    This function need to be defined as:

    collation(string $string1, string $string2): int

    Valori restituiti

    Restituisce true in caso di successo, false in caso di fallimento.

    Esempi

    Example #1 Pdo\Sqlite::createCollation() example

    <?php
    $db     = new Pdo\Sqlite('sqlite::memory:');
    $db->exec("CREATE TABLE test (col1 string)");
    $db->exec("INSERT INTO test VALUES ('a1')");
    $db->exec("INSERT INTO test VALUES ('a10')");
    $db->exec("INSERT INTO test VALUES ('a2')");

    $db->sqliteCreateCollation('NATURAL_CMP', 'strnatcmp');
    foreach (    $db->query("SELECT col1 FROM test ORDER BY col1") as $row) {
    echo     $row['col1'] . "\n";
    }
    echo     "\n";
    foreach (    $db->query("SELECT col1 FROM test ORDER BY col1 COLLATE NATURAL_CMP") as $row) {
    echo     $row['col1'] . "\n";
    }
    ?>

    Il precedente esempio visualizzerà:

    a1
a10
a2

a1
a2
a10

    Vedere anche:

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