Question

我编写了这个PHP代码，用于从JSON文件中提取值并将它们插入到MySQL数据库中。

<?php
//connect to mysql db
$con = mysqli_connect("localhost","root","","db_tweets") or die('Could not connect: ' . mysql_error());

//read the json file contents
$jsondata = file_get_contents('prova.json');

//convert json object to php associative array
$data = json_decode($jsondata, true);

foreach ($data as $u => $z){
    foreach ($z as $n => $line){
        //get the tweet details
        $text = $line['text'];
        $id_tweet = $line['id_str'];
        $date = $line['created_at'];
        $id_user = $line['user']['id_str'];
        $screen_name = $line['user']['screen_name'];
        $name = $line['user']['name'];

        $sqlu = "INSERT INTO user(id_user, screen_name, name)
            VALUES ('".$id_user."', '".$screen_name."', '".$name."')";
    }
}
if(!mysqli_query($con, $sqlu))
{
    die('Error : ' . mysql_error());
}
?>

这样做会将值始终插入表格的第一行，覆盖以前的值。所以它仍然只是最后一个。

我怎么能：

1）将所有值插入多行？

2）解析多个JSON文件？

Answer 1

试试这个。您只是在执行最后一个查询，因为mysqli_query()在外部循环。

方法1：

<?php
//connect to mysql db
$con = mysqli_connect("localhost","root","","db_tweets") or die('Could not connect: ' . mysql_error());

//read the json file contents
$jsondata = file_get_contents('prova.json');

//convert json object to php associative array
$data = json_decode($jsondata, true);

foreach ($data as $u => $z){
    foreach ($z as $n => $line){
        //get the tweet details
        $text = $line['text'];
        $id_tweet = $line['id_str'];
        $date = $line['created_at'];
        $id_user = $line['user']['id_str'];
        $screen_name = $line['user']['screen_name'];
        $name = $line['user']['name'];

        $sqlu = "INSERT INTO user(id_user, screen_name, name)
            VALUES ('".$id_user."', '".$screen_name."', '".$name."')";
       if(!mysqli_query($con, $sqlu))
       {
           die('Error : ' . mysql_error());
       }
    }
}
?>

方法2：

<?php

//connect to mysql db
$con = mysqli_connect("localhost","root","","db_tweets") or die('Could not connect: ' . mysql_error());

//read the json file contents
$jsondata = file_get_contents('prova.json');

//convert json object to php associative array
$data = json_decode($jsondata, true);

$values = "";
foreach ($data as $u => $z){
    foreach ($z as $n => $line){
        //get the tweet details
        $text = $line['text'];
        $id_tweet = $line['id_str'];
        $date = $line['created_at'];
        $id_user = $line['user']['id_str'];
        $screen_name = $line['user']['screen_name'];
        $name = $line['user']['name'];

        $values .= "('".$id_user."', '".$screen_name."', '".$name."'),";
    }
}

if(!empty($values)) {
    $values = substr($values, 0, -1);
    $sqlu = "INSERT INTO user(id_user, screen_name, name) VALUES {$values}";
    if(!mysqli_query($con, $sqlu))
    {
        die('Error : ' . mysql_error());
    }
}
?>

回答多个文件：

<?php

//connect to mysql db
$con = mysqli_connect("localhost","root","","db_tweets") or die('Could not connect: ' . mysql_error());

$files = array("prova.json", "file2.json");

foreach ($files as $file) {
//read the json file contents
    $jsondata = file_get_contents($file);

//convert json object to php associative array
    $data = json_decode($jsondata, true);

    $values = "";
    foreach ($data as $u => $z) {
        foreach ($z as $n => $line) {
            //get the tweet details
            $text = $line['text'];
            $id_tweet = $line['id_str'];
            $date = $line['created_at'];
            $id_user = $line['user']['id_str'];
            $screen_name = $line['user']['screen_name'];
            $name = $line['user']['name'];

            $values .= "('" . $id_user . "', '" . $screen_name . "', '" . $name . "'),";
        }
    }

    if (!empty($values)) {
        $values = substr($values, 0, -1);
        $sqlu = "INSERT INTO user(id_user, screen_name, name) VALUES {$values}";
        if (!mysqli_query($con, $sqlu)) {
            die('Error : ' . mysql_error());
        }
    }
}
?>

Answer 2

对于每个循环，在循环之后将该变量传递给$sqlu函数之前，您将覆盖最后的mysqli_query值。因此，一旦完成循环，您就会将最后指定的值留给$sqlu，并且这是唯一被执行的值。

相反，在循环中执行查询并...

使用PHP mysqli_函数mysqli_prepare，mysqli_stmt_bind_param和mysqli_stmt_execute来简化和保护您的查询：

//connect to mysql db
$con = mysqli_connect("localhost","root","","db_tweets") or die('Could not connect: ' . mysql_error());

// prepare your insert query
$stmt = mysqli_prepare($con, 'INSERT INTO user(id_user, screen_name, name) VALUES (?, ?, ?)');

// bind the upcoming variable names to the query statement
mysqli_stmt_bind_param($stmt, 'iss', $id_user, $screen_name, $name);

// loop over JSON files
$jsonfiles = array('prova.json', 'provb.json', 'provc.json');
foreach ( $jsonfiles as $jsonfile ) {

    //read the json file contents
    $jsondata = file_get_contents($jsonfile);   

    //convert json object to php associative array
    $data = json_decode($jsondata, true);

    foreach ($data as $u => $z){
        foreach ($z as $n => $line){
            //get the tweet details
            $id_user = $line['user']['id_str'];
            $screen_name = $line['user']['screen_name'];
            $name = $line['user']['name'];

            // execute this insertion
            mysqli_stmt_execute($stmt);
        }
    }
}

因此，这不仅可以通过准备一次查询来使用更少的数据库资源，并且具有更清晰的代码，而且还可以正确地转义插入值以防止sql注入。

添加了一个包含任意数量的JSON文件名的数组$jsonfiles，并使用foreach构造循环遍历JSON文件。

使用PHP将JSON文件中的多行和文档插入MySQL数据库

2 个答案: