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    SQLite3::createCollation

    (PHP 5 >= 5.3.11, PHP 7, PHP 8)

    SQLite3::createCollation — Registers a PHP function for use as an SQL collating function

    Descrizione

    public SQLite3::createCollation(string $name, callable $callback): bool

    Registers a PHP function or user-defined function for use as a collating function within SQL statements.

    Elenco dei parametri

    name

    Name of the SQL collating function to be created or redefined

    callback

    The name of a PHP function or user-defined function to apply as a callback, defining the behavior of the collation. It should accept two values and return as strcmp() does, i.e. it should return -1, 1, or 0 if the first string sorts before, sorts after, or is equal to the second.

    This function need to be defined as:

    collation(mixed $value1, mixed $value2): int

    Valori restituiti

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

    Esempi

    Example #1 SQLite3::createCollation() example

    Register the PHP function strnatcmp() as a collating sequence in the SQLite3 database.

    <?php

    $db     = new SQLite3(":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->createCollation('NATURAL_CMP', 'strnatcmp');

    $defaultSort = $db->query("SELECT col1 FROM test ORDER BY col1");
    $naturalSort = $db->query("SELECT col1 FROM test ORDER BY col1 COLLATE NATURAL_CMP");

    echo     "default:\n";
    while (    $row = $defaultSort->fetchArray()){
    echo     $row['col1'], "\n";
    }

    echo     "\nnatural:\n";
    while (    $row = $naturalSort->fetchArray()){
    echo     $row['col1'], "\n";
    }

    $db->close();

    ?>

    Il precedente esempio visualizzerà:

    
default:
a1
a10
a2

natural:
a1
a2
a10

    Vedere anche:

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