Question

这是对我试图解释previously的问题的更好解释。

我希望执行所有使用相同预准备语句的多个查询，如下所示（工作代码）：

$params = [
    ['age'=>10,'id'=>1], ['age'=>12,'id'=>2],
];
$param_types = 'ii';
$sql_template = "UPDATE mytable SET age = ? WHERE id = ?";
$stmt = $mysqli->prepare($sql_template);
$stmt->bind_param($param_types, $age, $id);

foreach($params as $param):
    $age = $param['age'];
    $id = $param['id'];
    $stmt->execute();
endforeach;

我想把这个逻辑放在一个函数中，然后像这样使用它：

queries_from_template($sql_template, $params, $param_types);

由于我不知道$params会是什么样子，我一直试图弄清楚如何编写这个函数。以下是我到目前为止的情况：

function queries_from_template($sql_template,$params,$param_types){

    //$mysqli is a handle to a live mysqli DB connection
    $stmt = $mysqli->prepare($sql_template);

    //build the array that holds the arguments of $stmt->bind_param
    //result will be eg: ['ii', 10, 1]
    $bind_param_args = array_merge([$param_types],array_values($params[0]));

    //call bind_param with a dynamic number of arguments
    call_user_func_array([$stmt,"bind_param"],$bind_param_args);

    foreach($params as $param):
        /* THIS IS WHERE I'M STUCK*/
        // I need a handle to each of the parameters that were bound with
        // bind_param so that I can set them to the correct value
        // on each loop before I execute.
        // Remember I don't know how many parameters there are

        //run query with current value of parameters
        $stmt->execute();
    endforeach;

    //todo: free results, close connection, disconnect
}

Answer 1

由于用于引用$stmt->bind_param(...)中的参数的特定var名称并不重要，我将输入从关联数组更改为索引数组

在：

$params = [
    ['age'=>10,'id'=>1], ['age'=>12,'id'=>2],
];

现在：

$params = [
    [10,1], [12,2],
];

这样可以更轻松地遍历每个查询的参数。以下是我的解决方案：

/*
 * Executes multiple queries from the same prepared statement
 */
function queries_from_template($sql_template, $params, $param_types){
    $stmt = $mysqli->prepare($sql_template);

    $handles = [];//holds references to parameters
    for($i=0; $i<count($params[0]);$i++):
        $varname = "param_$i";
        $$varname = null; //define variables $param_0, $param_1...
        $handles[] = &$$varname; //store references to the new variables
    endfor;

    //call $stmt->bind_param: bind to the new variables
    $bind_param_args = array_merge([$param_types],$handles);
    call_user_func_array([$stmt,'bind_param'],$bind_param_args);

    foreach($params as $param):
        foreach($handles as $index => &$handle):
            // assign the values for the current execute loop
            // to the created vars ($param_0, $param_1...)
            $handle = $param[$index];
        endforeach;

        $stmt->execute(); //execute, todo: error handling          
    endforeach;

    $stmt->close(); $mysqli->close();
}

Answer 2

// Associated sets
$params_sets = [
    ['age'=>10,'id'=>1], 
    ['age'=>12,'id'=>2],
];

// Param names in right order
$param_names = ['age', 'id'];

// Param types in right order
$param_types = 'ii';

// SQL template
$sql_template = "UPDATE mytable SET age = ? WHERE id = ?";

$stmt = $mysqli->prepare($sql_template);

// Ok, let's do it!
foreach ($params_sets as $params) {
    // Collecting parameters for bind_param function 
    // You need to do it every iteration!
    // First parameter is $param_types
    $bind_params = [$param_types];
    // Now let's add every parameter in right order using $param_names
    foreach ($param_names as $param_name) {
        $bind_params[] = $params[$param_name];
    }
    // Ok! Call bind_param method from $stmt object with $bind_params as parameters
    call_user_func_array([$stmt, 'bind_param'], $bind_params);
    // And execute query
    $stmt->execute();
}

祝你好运！

许多php mysqli查询来自一个预准备语句而不知道有多少参数

2 个答案: