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mysqli_stmt_bind_result

(PHP 5)

mysqli_stmt_bind_result

(no version information, might be only in CVS)

stmt->bind_result -- Binds variables to a prepared statement for result storage

Description

Procedural style:

bool mysqli_stmt_bind_result ( mysqli_stmt stmt, mixed &var1 [, mixed &...] )

Object oriented style (method):

class mysqli_stmt {

bool bind_result ( mixed &var1 [, mixed &...] )

}

mysqli_stmt_bind_result() is used to associate (bind) columns in the result set to variables. When mysqli_stmt_fetch() is called to fetch data, the MySQL client/server protocol places the data for the bound columns into the specified variables var1, ....

注: Note that all columns must be bound prior to calling mysqli_stmt_fetch(). Depending on column types bound variables can silently change to the corresponding PHP type.

A column can be bound or rebound at any time, even after a result set has been partially retrieved. The new binding takes effect the next time mysqli_stmt_fetch() is called.

返回值

如果成功则返回 TRUE，失败则返回 FALSE。

参见

mysqli_stmt_bind_param(), mysqli_stmt_execute(), mysqli_stmt_fetch(), mysqli_prepare(), mysqli_stmt_prepare(), mysqli_stmt_init(), mysqli_stmt_errno() 和 mysqli_stmt_error().

范例

例子 1. Object oriented style

<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");

if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

/* prepare statement */
if ($stmt = $mysqli->prepare("SELECT Code, Name FROM Country ORDER BY Name LIMIT 5")) {
    $stmt->execute();

    /* bind variables to prepared statement */
    $stmt->bind_result($col1, $col2);

    /* fetch values */
    while ($stmt->fetch()) {
        printf("%s %s\n", $col1, $col2);
    }

    /* close statement */
    $stmt->close();
}
/* close connection */
$mysqli->close();

?>

例子 2. Procedural style

<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");

/* check connection */
if (!$link) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

/* prepare statement */
if ($stmt = mysqli_prepare($link, "SELECT Code, Name FROM Country ORDER BY Name LIMIT 5")) {
    mysqli_stmt_execute($stmt);

    /* bind variables to prepared statement */
    mysqli_stmt_bind_result($stmt, $col1, $col2);

    /* fetch values */
    while (mysqli_stmt_fetch($stmt)) {
        printf("%s %s\n", $col1, $col2);
    }

    /* close statement */
    mysqli_stmt_close($stmt);
}

/* close connection */
mysqli_close($link);
?>

上例将输出：

AFG Afghanistan
ALB Albania
DZA Algeria
ASM American Samoa
AND Andorra

add a note add a note User Contributed Notes
Michael Newton - http://mike.eire.ca/
14-Feb-2006 03:07
Windows users:

If you're having problems with this statement in general (not just with DECIMAL columns) try the latest client library from MySQL at http://dev.mysql.com/downloads/connector/php/ to see if it helps.

I couldn't even get the example code above working (using the very latest PHP and MySQL) but swapping in the later DLL files from MySQL fixed everything up.
andrey at php dot net
30-Nov-2005 06:49
[ATTENTION] When connecting with 4.1.x libmysql (on windows there is no other option) to 5.0 (5.1) MySQL server there is incompatibility in the protocol regarding type DECIMAL. Therefore result binding on decimal column is not possible. In this case normal mysqli_query() has to be used!!!
When trying to bind you will get FALSE if one of the columns is DECIMAL.
thejkwhosaysni at gmail dot com
20-Oct-2005 04:12
I've created these functions which will act like mysqli_fetch_array() and mysqli_fetch_object() but work with bound results.

<?
   function fetch_object() {
       $data = mysqli_stmt_result_metadata($this->stmt);
       $count = 1; //start the count from 1. First value has to be a reference to stmt.
       $fieldnames[0] = &$this->stmt;
       $obj = new stdClass;
       while ($field = mysqli_fetch_field($data)) {
           $fn = $field->name; //get all the feild names
           $fieldnames[$count] = &$obj->$fn; //load the fieldnames into an object..
           $count++;
       }
       call_user_func_array(mysqli_stmt_bind_result, $fieldnames);
       mysqli_stmt_fetch($this->stmt);
       return $obj;
   }

   function fetch_array() {
       $data = mysqli_stmt_result_metadata($this->stmt);
       $count = 1; //start the count from 1. First value has to be a reference to the stmt. because bind_param requires the link to $stmt as the first param.
       $fieldnames[0] = &$this->stmt;
       while ($field = mysqli_fetch_field($data)) {
           $fieldnames[$count] = &$array[$field->name]; //load the fieldnames into an array.
           $count++;
       }
       call_user_func_array(mysqli_stmt_bind_result, $fieldnames);
       mysqli_stmt_fetch($this->stmt);
       return $array;

   }

?>

Hope this helps some people, I was puzzled by this for a while.
andrey at php dot net
07-Oct-2005 08:38
If you select LOBs use the following order of execution or you risk mysqli allocating more memory that actually used

1)prepare()
2)execute()
3)store_result()
4)bind_result()

If you skip 3) or exchange 3) and 4) then mysqli will allocate memory for the maximal length of the column which is 255 for tinyblob, 64k for blob(still ok), 16MByte for MEDIUMBLOB - quite a lot and 4G for LONGBLOB (good if you have so much memory). Queries which use this order a bit slower when there is a LOB but this is the price of not having memory exhaustion in seconds.
matti at withoutthis dot keller dot com
25-Jul-2005 10:30
Hi
I saw a bit of discussion about using mysqli_stmt_bin_result dynamically, without knowing exactly how many columns will be returned.
After a while i developed this snippet to mimic the same behaviour as mysql_fetch_array():
<?php
# of fields in result set.
$nof = mysqli_num_fields( mysqli_stmt_result_metadata($handle) );

# The metadata of all fields
$fieldMeta = mysqli_fetch_fields( mysqli_stmt_result_metadata($handle) );
      
# convert it to a normal array just containing the field names
$fields = array();
for($i=0; $i < $nof; $i++)
   $fields[$i] = $fieldMeta[$i]->name;

# The idea is to get an array with the result values just as in mysql_fetch_assoc();
# But we have to use call_user_func_array to pass the right number of args ($nof+1)
# So we create an array:
# array( $stmt, &$result[0], &$result[1], ... )
# So we get the right values in $result in the end!

# Prepare $result and $arg (which will be passed to bind_result)
$result = array();
$arg = array($this->stmt);
for ($i=0; $i < $nof; $i++) {
   $result[$i] = '';
   $arg[$i+1] = &$result[$i];
}

call_user_func_array ('mysqli_stmt_bind_result',$arg);

# after mysqli_stmt_fetch(), our result array is filled just perfectly,
# but it is numbered (like in mysql_fetch_array() ), not indexed by field name!
# If you just want to mimic that ones behaviour you can stop here :)

mysqli_stmt_fetch($this->stmt);

# Now you can use $result
print_r($result);

# But beware! when using the fetch in a loop, always COPY $result or else you might
# end with all the same values because of the references
?>
Hope that this will help someone....
Matt
brad dot jackson at resiideo dot com
23-Mar-2005 01:10
A potential problem exists in binding result parameters from a prepared statement which reference large datatypes like mediumblobs.  One of our database tables contains a table of binary image data.  Our largest image in this table is around 50Kb, but even so the column is typed as a mediumblob to allow for files larger than 64Kb.  I spent a frustrating hour trying to figure out why mysqli_stmt_bind_result choked while trying to allocate 16MB of memory for what should have been at most a 50Kb result, until I realized the function is checking the column type first to find out how big a result _might_ be retrieved, and attempting to allocate that much memory to contain it.  My solution was to use a more basic mysqli_result() query.  Another option might have been to retype the image data column as blob (64Kb limit).
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