A brief analysis of how PHP converts database data into an array

PHP is a widely used server-side programming language commonly used for the development of web applications. When we need to retrieve data from the database, PHP provides a convenient method to convert the data in the database into an array for easy data display or processing on the web page.

This article will introduce how to use PHP to convert data in the database into an array.

1. Connect to the database

First, we need to use PHP to connect to the database. Before connecting to the database, you need to determine the database type, host name, user name, password, port number and other information. The following is a sample code for using the mysqli_connect() function to connect to the database:

<?php
$host = "localhost"; // 数据库主机名
$user = "username"; // 数据库用户名
$password = "password"; // 数据库密码
$dbname = "database_name"; // 数据库名称
$port = 3306; // 数据库端口
 
// 连接数据库
$mysqli = mysqli_connect($host, $user, $password, $dbname, $port);
 
// 检查连接是否成功
if (!$mysqli) {
    die("连接数据库失败：" . mysqli_connect_error());
}
?>

2. Query data

After connecting to the database, you need to use SQL statements to query the data. The following is a sample code for querying data using the mysqli_query() function:

<?php
$sql = "SELECT * FROM table_name"; // SQL语句
 
$result = mysqli_query($mysqli, $sql); // 执行SQL语句
 
// 检查查询是否成功
if (!$result) {
    die("查询失败：" . mysqli_error($mysqli));
}
?>

After the query is successful, we can use the mysqli_fetch_array() function to convert the query results into an array. The following is a sample code that uses the mysqli_fetch_array() function to query data and convert the results into an array:

<?php
$sql = "SELECT * FROM table_name"; // SQL语句
 
$result = mysqli_query($mysqli, $sql); // 执行SQL语句
 
// 检查查询是否成功
if (!$result) {
    die("查询失败：" . mysqli_error($mysqli));
}
 
// 将查询结果转换成数组
$data = array();
while ($row = mysqli_fetch_array($result, MYSQLI_ASSOC)) {
    $data[] = $row;
}
?>

Among them, the MYSQLI_ASSOC parameter indicates that the returned result array only contains the associated index, that is, the column name.

3. Output results

After converting the query results into an array, we can perform further processing or output the results to the web page. The following is a sample code that outputs query results to a web page:

<?php
$sql = "SELECT * FROM table_name"; // SQL语句
 
$result = mysqli_query($mysqli, $sql); // 执行SQL语句
 
// 检查查询是否成功
if (!$result) {
    die("查询失败：" . mysqli_error($mysqli));
}
 
// 将查询结果转换成数组
$data = array();
while ($row = mysqli_fetch_array($result, MYSQLI_ASSOC)) {
    $data[] = $row;
}
 
// 输出结果到网页
foreach ($data as $item) {
    echo $item[&#39;column_name&#39;] . "<br>";
}
?>

Among them, $item['column_name'] represents the value of a column in the output result array.

Summary

In PHP, we can use the mysqli_connect() function to connect to the database, use the mysqli_query() function to query data, and use the mysqli_fetch_array() function to convert the query results into an array. By converting query results into arrays, we can easily process and output data.

The above is how to use PHP to convert database data into an array. I hope it will be helpful to you.

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