How to implement image query and display function in php

In website development, image transmission is a very important function. Among them, PHP query image transmission is a common implementation method. It allows users to query related pictures in the database by entering keywords and display them on the web page for users to view and download.

There are many ways to implement PHP query and display images. Below we will introduce a common implementation method.

1. Establish database and data table

First, we need to create a picture table in the MySQL database to store information about all pictures. The structure of the table is as follows:

CREATE TABLE pic (
 id int(10) unsigned NOT NULL AUTO_INCREMENT COMMENT '主键ID',
 title varchar(100) NOT NULL DEFAULT '' COMMENT '图片标题',
 description varchar(255) NOT NULL DEFAULT '' COMMENT '图片描述',
 url varchar(255) NOT NULL DEFAULT '' COMMENT '图片URL',
 created datetime NOT NULL DEFAULT '0000-00-00 00:00:00' COMMENT '创建时间',
 PRIMARY KEY (id)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8mb4 COMMENT='图片存储表';

2. Create a PHP connection

In order to connect to the database and perform query operations, we need to create a PHP connection. You can use mysqli or PDO and other connection methods. The following is a sample code for mysqli connection:

//数据库连接配置
define('DB_HOST', 'localhost');
define('DB_DATABASE', 'test');
define('DB_USERNAME', 'root');
define('DB_PASSWORD', '');
//连接数据库
$mysqli = new mysqli(DB_HOST, DB_USERNAME, DB_PASSWORD, DB_DATABASE);
if ($mysqli->connect_errno) {
die('Connect Error: ' . $mysqli->connect_error);
}

3. Write the query function

After connecting to the database, we need to write the query function. Usually, the user will enter a keyword to query, and we need to compare it with the title and description in the database, and return the matching image URL to the user. The following is a basic query code:

//定义查询关键字
$keyword = $_GET['keyword'];
//执行查询
$query = "SELECT * FROM pic WHERE title LIKE '%$keyword%' OR description LIKE '%$keyword%'";
$result = $mysqli->query($query);
//处理查询结果
$pic_arr = array();
if ($result) {
while ($row = $result->fetch_assoc()) {
    $pic_arr[] = array(
        'title' => $row['title'],
        'description' => $row['description'],
        'url' => $row['url'],
    );
}
}

4. Display query results

Finally, we need to display the query results on the web page for users to view and download. This can be implemented using technologies such as HTML and CSS. The following is a basic display code:

//遍历所有查询结果
foreach ($pic_arr as $pic) {
echo &#39;<div class="pic">&#39;;
echo &#39;<img src="&#39;.$pic[&#39;url&#39;].&#39;" />&#39;;
echo &#39;<h3>&#39;.$pic[&#39;title&#39;].&#39;</h3>&#39;;
echo &#39;<p>&#39;.$pic[&#39;description&#39;].&#39;</p>&#39;;
echo &#39;</div>&#39;;
}

Through the above steps, we can implement a simple PHP image query and display function. However, in actual projects, related functions such as image uploading and watermark adding may also need to be considered to meet actual needs.

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