动态绑定mysqli_stmt参数，然后绑定结果（PHP）

Question

我正在尝试动态绑定mysql_stmt参数，并在关联数组中获取结果。 我在stackoverflow上找到了这篇文章，其中Amber用以下代码发布了答案：

原始文章： 如何使用准备好的语句制作适当的mysqli扩展类？

“假设您实际上是想编写自己的版本（相对于利用现有库之一而言，其他答案已经提出了建议-这些也是不错的选择）...

这里有一些功能可能对您检查有用。 第一个允许您将查询结果绑定到关联数组，第二个允许您传入两个数组，一个传递键的有序数组，另一个传递这些键的数据的关联数组并将该数据绑定到准备好的声明：”

function stmt_bind_assoc (&$stmt, &$out) {
    $data = mysqli_stmt_result_metadata($stmt);
    $fields = array();
    $out = array();

$fields[0] = $stmt;
$count = 1;

while($field = mysqli_fetch_field($data)) {
    $fields[$count] = &$out[$field->name];
    $count++;
}
call_user_func_array(mysqli_stmt_bind_result, $fields);

}

function stmt_bind_params($stmt, $fields, $data) {
    // Dynamically build up the arguments for bind_param
    $paramstr = '';
    $params = array();
    foreach($fields as $key)
    {
        if(is_float($data[$key]))
            $paramstr .= 'd';
        elseif(is_int($data[$key]))
            $paramstr .= 'i';
        else
            $paramstr .= 's';
        $params[] = $data[$key];
    }
    array_unshift($params, $stmt, $paramstr);
    // and then call bind_param with the proper arguments
    call_user_func_array('mysqli_stmt_bind_param', $params);
}

我尝试研究代码以了解它的作用，并且使第二个功能正常工作，但我不知道应该如何使用第一个功能。 如何使用它检索类似于mysqli_result :: fetch_assoc（）的数组？

我希望能够像以前一样使用结果：

while ($row = mysql_fetch_array($result)){
  echo $row['foo']." ".$row['bar'];
}

请帮助我在此方面取得一些进展:)

Answer 1

好的，这是一种方法：

编辑，以修复获取多行时的错误

$sql = "SELECT `first_name`,`last_name` FROM `users` WHERE `country` =? AND `state`=?";
$params = array('Australia','Victoria');

/*
    In my real app the below code is wrapped up in a class 
    But this is just for example's sake.
    You could easily throw it in a function or class
*/

// This will loop through params, and generate types. e.g. 'ss'
$types = '';                        
foreach($params as $param) {        
    if(is_int($param)) {
        $types .= 'i';              //integer
    } elseif (is_float($param)) {
        $types .= 'd';              //double
    } elseif (is_string($param)) {
        $types .= 's';              //string
    } else {
        $types .= 'b';              //blob and unknown
    }
}
array_unshift($params, $types);

// Start stmt
$query = $this->connection->stmt_init(); // $this->connection is the mysqli connection instance
if($query->prepare($sql)) {

    // Bind Params
    call_user_func_array(array($query,'bind_param'),$params);

    $query->execute(); 

    // Get metadata for field names
    $meta = $query->result_metadata();

    // initialise some empty arrays
    $fields = $results = array();

    // This is the tricky bit dynamically creating an array of variables to use
    // to bind the results
    while ($field = $meta->fetch_field()) { 
        $var = $field->name; 
        $$var = null; 
        $fields[$var] = &$$var; 
    }


    $fieldCount = count($fieldNames);

// Bind Results                                     
call_user_func_array(array($query,'bind_result'),$fields);

$i=0;
while ($query->fetch()){
    for($l=0;$l<$fieldCount;$l++) $results[$i][$fieldNames[$l]] = $fields[$fieldNames[$l]];
    $i++;
}

    $query->close();

    // And now we have a beautiful
    // array of results, just like
    //fetch_assoc
    echo "<pre>";
    print_r($results);
    echo "</pre>";
}

Answer 2

如果只选择一行，则来自伊曼纽尔的答案会很好！ 如果查询选择了多行，则$ results-Array会为每行保留一个结果，但结果始终填充有最后一个条目。 在fetch（）中稍作更改，即可正常运行。

$ sqlStmt是一个字符串，填充了mysql-query

$ params是一个数组，填充了应该传递的变量

$ results是一个空数组，保存结果

    if (!is_string($sqlStmt) || empty($sqlStmt)) {
        return false;
    }

    // initialise some empty arrays
    $fields = array();
    $results = array();

    if ($stmt = $this->prepare($sqlStmt)) {
        // bind params if they are set
        if (!empty($params)) {
            $types = '';
            foreach($params as $param) {
                // set param type
                if (is_string($param)) {
                    $types .= 's';  // strings
                } else if (is_int($param)) {
                    $types .= 'i';  // integer
                } else if (is_float($param)) {
                    $types .= 'd';  // double
                } else {
                    $types .= 'b';  // default: blob and unknown types
                }
            }

            $bind_names[] = $types;
            for ($i=0; $i<count($params);$i++) {
                $bind_name = 'bind' . $i;       
                $$bind_name = $params[$i];      
                $bind_names[] = &$$bind_name;   
            }

            call_user_func_array(array($stmt,'bind_param'),$bind_names);
        }

        // execute query
        $stmt->execute();

        // Get metadata for field names
        $meta = $stmt->result_metadata();

        // This is the tricky bit dynamically creating an array of variables to use
        // to bind the results
        while ($field = $meta->fetch_field()) { 
            $var = $field->name; 
            $$var = null; 
            $fields[$var] = &$$var;
        }

        // Bind Results
        call_user_func_array(array($stmt,'bind_result'),$fields);

        // Fetch Results
        $i = 0;
        while ($stmt->fetch()) {
            $results[$i] = array();
            foreach($fields as $k => $v)
                $results[$i][$k] = $v;
            $i++;
        }

        // close statement
        $stmt->close();
    }

Answer 3

只是将@Emmanuel和@matzino的出色答案与通过mysqli选择PDO可以获得的代码进行比较：

$sql = "SELECT `first_name`,`last_name` FROM `users` WHERE `country` =? AND `state`=?";
$params = array('Australia','Victoria');

$stm = $query->prepare($sql);
$stm->execute($params); 
$results = $stm->fetchAll(); // or fetch() or fetchColumn() depends on expected type

哎呀，仅此而已？

Answer 4

使用上面的答案后，我发现自己需要进行一些清理，尤其是“ fieldNames []”部分。 下面的代码是过程样式。 我希望它对某人有用。

我从我可以动态查询数据的类中剪切了代码。 为了方便阅读，我删除了一些内容。 在课堂上，我允许用户定义定义表和外键，以便限制前端的数据输入以及所述相关数据的筛选和排序选项。 这些都是我删除的所有参数以及自动查询生成器。

$query = "SELECT `first_name`,`last_name` FROM `users` WHERE `country` =? AND `state`=?";
$params = array('Australia','Victoria');

////////////// GENERATE PARAMETER TYPES IF ANY //////////////
// This will loop through parameters, and generate types. ex: 'ss'
$types = '';
$params_size = sizeof($params);
if($params_size > 0)
{
    foreach($params as $param)
    {
        if(is_int($param))
        {
            $types .= 'i';              //integer
        }else if(is_float($param))
        {
            $types .= 'd';              //double
        }else if(is_string($param))
        {
            $types .= 's';              //string
        }else
        {
            $types .= 'b';              //blob and unknown
        }
    }
    array_unshift($params, $types);
}
////////////////////////////////////////////////////////////


// This is the tricky part to dynamically create an array of
// variables to use to bind the results

//below from http://php.net/manual/en/mysqli-result.fetch-field.php
/*
name        The name of the column
orgname     Original column name if an alias was specified
table       The name of the table this field belongs to (if not calculated)
orgtable    Original table name if an alias was specified
def         Reserved for default value, currently always ""
db          Database (since PHP 5.3.6)
catalog     The catalog name, always "def" (since PHP 5.3.6)
max_length  The maximum width of the field for the result set.
length      The width of the field, as specified in the table definition.
charsetnr   The character set number for the field.
flags       An integer representing the bit-flags for the field.
type        The data type used for this field
decimals    The number of decimals used (for integer fields)
*/

/// FIELD TYPE REFERENCE ///
/*
numerics
-------------
BIT: 16
TINYINT: 1
BOOL: 1
SMALLINT: 2
MEDIUMINT: 9
INTEGER: 3
BIGINT: 8
SERIAL: 8
FLOAT: 4
DOUBLE: 5
DECIMAL: 246
NUMERIC: 246
FIXED: 246

dates
------------
DATE: 10
DATETIME: 12
TIMESTAMP: 7
TIME: 11
YEAR: 13

strings & binary
------------
CHAR: 254
VARCHAR: 253
ENUM: 254
SET: 254
BINARY: 254
VARBINARY: 253
TINYBLOB: 252
BLOB: 252
MEDIUMBLOB: 252
TINYTEXT: 252
TEXT: 252
MEDIUMTEXT: 252
LONGTEXT: 252
*/

if($stmt = mysqli_prepare($db_link, $query))
{
    // BIND PARAMETERS IF ANY //
    if($params_size > 0)
    {
        call_user_func_array(array($stmt, 'bind_param'), makeValuesReferenced($params));
    }

    mysqli_stmt_execute($stmt);

    $meta = mysqli_stmt_result_metadata($stmt);


    $field_names = array();
    $field_length = array();
    $field_type = array();
    $output_data = array();

    /// THIS GET THE NAMES OF THE FIELDS AND ASSIGNS NEW VARIABLES USING THE FIELD NAME. THESE VARIABLES ARE THEN SET TO NULL ///
    $count = 0;
    while($field = mysqli_fetch_field($meta))
    {
        $field_names[$count] = $field->name;// field names
        $var = $field->name;
        $$var = null;
        $field_names_variables[$var] = &$$var;// fields variables using the field name
        $field_length[$var] = $field->length;// field length as defined in table
        $field_type[$var] = $field->type;// field data type as defined in table (numeric return)
        $count++;
    }
    setFieldLengthInfo($field_length);
    setFieldTypesInfo($field_type);

    $field_names_variables_size = sizeof($field_names_variables);
    call_user_func_array(array($stmt, 'bind_result'), $field_names_variables);

    $count = 0;
    while(mysqli_stmt_fetch($stmt))
    {
        for($l = 0; $l < $field_names_variables_size; $l++)
        {
            $output_data[$count][$field_names[$l]] = $field_names_variables[$field_names[$l]];/// THIS SETS ALL OF THE FINAL DATA USING THE DYNAMICALLY CREATED VARIABLES ABOVE
        }
        $count++;
    }
    mysqli_stmt_close($stmt);


    echo "<pre>";
    print_r($output_data);
    echo "</pre>";
}


function makeValuesReferenced($arr)
{
    $refs = array();
    foreach($arr as $key => $value)
        $refs[$key] = &$arr[$key];
    return $refs;
}