betterCode() PHP 2025

    SQLite3::openBlob

    (PHP 5 >= 5.3.0, PHP 7, PHP 8)

    SQLite3::openBlob — Opens a stream resource to read a BLOB

    Опис

    public SQLite3::openBlob(
        string $table,
        string $column,
        int $rowid,
        string $database = "main",
        int $flags = SQLITE3_OPEN_READONLY
    ): resource|false

    Opens a stream resource to read or write a BLOB, which would be selected by:

    SELECT column FROM database.table WHERE rowid = rowid

    Зауваження: It is not possible to change the size of a BLOB by writing to the stream. Instead, an UPDATE statement has to be executed, possibly using SQLite's zeroblob() function to set the desired BLOB size.

    Параметри

    table

    The table name.

    column

    The column name.

    rowid

    The row ID.

    database

    The symbolic name of the DB

    flags

    Either SQLITE3_OPEN_READONLY or SQLITE3_OPEN_READWRITE to open the stream for reading only, or for reading and writing, respectively.

    Значення, що повертаються

    Returns a stream resource, або false в разі помилки.

    Журнал змін

    Версія Опис
    7.2.0 The flags parameter has been added, allowing to write BLOBs; formerly only reading was supported.

    Приклади

    Приклад #1 SQLite3::openBlob() example

    <?php
    $conn     = new SQLite3(':memory:');
    $conn->exec('CREATE TABLE test (text text)');
    $conn->exec("INSERT INTO test VALUES ('Lorem ipsum')");
    $stream = $conn->openBlob('test', 'text', 1);
    echo     stream_get_contents($stream);
    fclose($stream); // mandatory, otherwise the next line would fail
    $conn->close();
    ?>

    Поданий вище приклад виведе:

    Lorem ipsum

    Приклад #2 Incrementally writing a BLOB

    <?php
    $conn     = new SQLite3(':memory:');
    $conn->exec('CREATE TABLE test (text text)');
    $conn->exec("INSERT INTO test VALUES (zeroblob(36))");
    $stream = $conn->openBlob('test', 'text', 1, 'main', SQLITE3_OPEN_READWRITE);
    for (    $i = 0; $i < 3; $i++) {
    fwrite($stream, "Lorem ipsum\n");
    }
    fclose($stream);
    echo     $conn->querySingle("SELECT text FROM test");
    $conn->close();
    ?>

    Поданий вище приклад виведе:

    Lorem ipsum
Lorem ipsum
Lorem ipsum

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