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    mysqli_result::data_seek

    mysqli_data_seek

    (PHP 5, PHP 7, PHP 8)

    mysqli_result::data_seek -- mysqli_data_seek — Adjusts the result pointer to an arbitrary row in the result

    Descrizione

    Stile orientato agli oggetti

    public mysqli_result::data_seek(int $offset): bool

    Stile procedurale

    mysqli_data_seek(mysqli_result $result, int $offset): bool

    The mysqli_data_seek() function seeks to an arbitrary result pointer specified by the offset in the result set.

    Elenco dei parametri

    result

    Solo nello stile procedurale: un identificatore di resultset restituito da mysqli_query(), mysqli_store_result() o mysqli_use_result().

    offset

    The row offset. Must be between zero and the total number of rows minus one (0..mysqli_num_rows() - 1).

    Valori restituiti

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

    Esempi

    Example #1 mysqli::data_seek() example

    Stile orientato agli oggetti

    <?php

    mysqli_report    (MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
    $mysqli = new mysqli("localhost", "my_user", "my_password", "world");

    $query = "SELECT Name, CountryCode FROM City ORDER BY Name";
    $result = $mysqli->query($query);

    /* Seek to row no. 401 */
    $result->data_seek(400);

    /* Fetch single row */
    $row = $result->fetch_row();

    printf("City: %s Countrycode: %s\n", $row[0], $row[1]);

    Stile procedurale

    <?php

    mysqli_report    (MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
    $link = mysqli_connect("localhost", "my_user", "my_password", "world");

    $query = "SELECT Name, CountryCode FROM City ORDER BY Name";

    $result = mysqli_query($link, $query);

    /* Seek to row no. 401 */
    mysqli_data_seek($result, 400);

    /* Fetch single row */
    $row = mysqli_fetch_row($result);

    printf ("City: %s Countrycode: %s\n", $row[0], $row[1]);

    I precedenti esempi visualizzeranno:

    City: Benin City  Countrycode: NGA

    Example #2 Adjusting the result pointer when iterating

    This function can be useful when iterating over the result set to impose a custom order or rewind the result set when iterating multiple times.

    <?php

    mysqli_report    (MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
    $mysqli = new mysqli("localhost", "my_user", "my_password", "world");

    $query = "SELECT Name, CountryCode FROM City ORDER BY Name LIMIT 15,4";
    $result = $mysqli->query($query);

    /* Iterate the result set in reverse order */
    for ($row_no = $result->num_rows - 1; $row_no >= 0; $row_no--) {
    $result->data_seek($row_no);

    /* Fetch single row */
    $row = $result->fetch_row();

    printf("City: %s Countrycode: %s\n", $row[0], $row[1]);
    }

    /* Reset pointer to the beginning of the result set */
    $result->data_seek(0);

    print     "\n";

    /* Iterate the same result set again */
    while ($row = $result->fetch_row()) {
    printf("City: %s Countrycode: %s\n", $row[0], $row[1]);
    }

    I precedenti esempi visualizzeranno:

    City: Acmbaro  Countrycode: MEX
City: Abuja  Countrycode: NGA
City: Abu Dhabi  Countrycode: ARE
City: Abottabad  Countrycode: PAK

City: Abottabad  Countrycode: PAK
City: Abu Dhabi  Countrycode: ARE
City: Abuja  Countrycode: NGA
City: Acmbaro  Countrycode: MEX

    Note

    Nota:

    This function can only be used with buffered results attained from the use of the mysqli_store_result(), mysqli_query() or mysqli_stmt_get_result() functions.

    Vedere anche:

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    User Contributed Notes 1 note

    up
    8
    kaisellgren at gmail dot com
    16 years ago
    This is useful function when you try to loop through the resultset numerous times.

    For example:

    <?php

    $result     = mysqli_query($connection_id,$query);

    while (    $row = mysqli_fetch_assoc($result))
    {
          // Looping through the resultset.
    }

    // Now if you need to loop through it again, you would first call the seek function:
    mysqli_data_seek($result,0);

    while (    $row = mysqli_fetch_assoc($result))
    {
          // Looping through the resultset again.
    }

    ?>
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