mysqli_result::data_seek

mysqli_data_seek

(PHP 5, PHP 7, PHP 8)

mysqli_result::data_seek -- mysqli_data_seekAdjusts 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($result400);

/* 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
32
kaisellgren at gmail dot com
14 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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