How to use PHP to implement a simple data import and export function

How to use PHP to implement a simple data import and export function

Importing and exporting data is a very common requirement in web development. As a popular server-side programming language, PHP provides a wealth of libraries and functions to process data. This article will introduce how to use PHP to implement a simple data import and export function, and provide specific code examples.

1. Data export

Data export is the process of extracting data from a database or other data source and outputting it as a file. In PHP, you can use the following steps to export data:

1.1 Connect to the database

First, you need to establish a connection with the database through PHP. In this example, a MySQL database is used as the data source. You can use the mysqli extension or PDO to connect to the database.

<?php
$servername = "localhost";
$username = "root";
$password = "password";
$dbname = "mydb";

// 使用mysqli扩展
$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 使用PDO
try {
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
}
catch(PDOException $e)
{
    echo "连接失败: " . $e->getMessage();
}
?>

1.2 Query data

Use SQL statements to query the data to be exported and save the results into an array.

<?php
$sql = "SELECT * FROM mytable";
$result = $conn->query($sql);

$data = array();
if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        $data[] = $row;
    }
}
?>

1.3 Export data

Export the data to a CSV file for subsequent import.

<?php
$filename = "export.csv";
$file = fopen($filename, 'w');

// 写入表头
$header = array_keys($data[0]);
fputcsv($file, $header);

// 写入数据
foreach ($data as $row) {
    fputcsv($file, $row);
}

fclose($file);
?>

2. Data import

Data import is the process of reading and inserting data stored in a file into a database or other data source. In PHP, you can use the following steps to implement data import:

2.1 Upload files

Create an HTML page containing a file upload form and upload the file to the server through the POST method.

<form action="import.php" method="POST" enctype="multipart/form-data">
    <input type="file" name="file" />
    <input type="submit" value="导入" />
</form>

2.2 Processing uploaded files

Process uploaded files in PHP scripts and save them to the server.

<?php
$target_dir = "/uploads/";
$target_file = $target_dir . basename($_FILES["file"]["name"]);
move_uploaded_file($_FILES["file"]["tmp_name"], $target_file);

// 文件路径
$filepath = $target_dir . $_FILES["file"]["name"];
?>

2.3 Import data

Read the contents of the CSV file and insert it into the database.

<?php
$file = fopen($filepath, 'r');

// 跳过表头
fgetcsv($file);

// 插入数据
while (($line = fgetcsv($file)) !== false) {
    $sql = "INSERT INTO mytable (field1, field2, field3) VALUES ('$line[0]', '$line[1]', '$line[2]')";
    $conn->query($sql);
}

fclose($file);
?>

The above code example demonstrates how to use PHP to implement a simple data import and export function. With these steps, you can easily export data from the database to a CSV file and import data from the CSV file into the database. Depending on the actual situation, you can modify and extend the code as needed.

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