php 动态绑定mysqli_stmt参数,然后绑定结果

xv8emn3q  于 2022-12-10  发布在  PHP
关注(0)|答案(4)|浏览(151)

我正在尝试动态绑定mysql_stmt参数,并在一个关联数组中获得结果。我在Stack Overflow上找到了这篇文章,Amber用下面的代码给出了答案:
原帖:如何使用预准备语句创建一个合适的mysqli扩展类?
“假设您真的想编写自己的版本(而不是使用其他答案建议的现有库之一--这些也是很好的选择)......
这里有两个函数,你可能会发现它们很有用。第一个函数允许你将查询结果绑定到一个关联数组,第二个函数允许你传入两个数组,一个是键的有序数组,另一个是这些键的数据的关联数组,并将这些数据绑定到一个准备好的语句中:“

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);
}

我试着学习代码来理解它的作用,我已经使第二个函数正常工作,但我不知道我应该做些什么来使用第一个函数.我如何使用它来检索类似于mysqli_result::的数组fetch_assoc()函数中的值?
我希望能够像你以前那样利用结果:

while ($row = mysql_fetch_array($result)){
  echo $row['foo']." ".$row['bar'];
}
u0njafvf

u0njafvf1#

好吧,这里有一个方法:

已编辑,以修复读取多行时的错误

$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>";
}
qij5mzcb

qij5mzcb2#

如果只选择一行,Emmanuel的答案就能很好地工作!如果查询选择了多行,$results-Array会为每一行保存一个结果,但结果总是用最后一个条目填充。在fetch()中做了一点改动--尽管它工作得很好。
$sqlStmt是一个字符串,用mysql-query填充
$params是一个数组,填充了应该传递的变量
$results是一个空数组,用于保存结果

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();
    }
57hvy0tb

57hvy0tb3#

如果你选择PDO而不是mysqli,那么你可以将@Emmanuel和@matzino给出的答案与你得到的代码进行比较:

$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

哦,就这些?

hkmswyz6

hkmswyz64#

在使用了上面的答案之后,我发现自己需要做一些清理,特别是'fieldNames[]'部分。下面的代码是过程化的。我希望它能对某些人有用。
我从我做的一个可以动态查询数据的类中删除了代码。为了让它更容易阅读,我删除了一些东西。在我的类中,我允许用户定义定义表和外键,以便限制前端的数据输入,以及相关数据的过滤和排序选项。这些都是我删除的参数,以及自动查询构建器。

$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;
}

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