How to implement scheduled database backup tasks in PHP

With the rapid development of the Internet, website data has become one of the most important assets of an enterprise. However, no matter what type of website it is, it is inevitable that data loss will occur. Therefore, database backup becomes very necessary. This article will introduce an automatic scheduled task method for writing database backup using PHP, which can not only ensure the security of data, but also reduce the workload of administrators.

1. The importance of backing up the database

Backing up the database is very important, and this is common sense that every website administrator should know. Whether it is due to hardware failure, hacker attacks or human errors, data may be lost. If there is no backup, the enterprise will face huge disaster.

In addition, another benefit of backing up the database is that it can help enterprises conduct better data analysis. Backups typically store data centrally on disk or other storage devices, and these backups can be used at any time for daily analysis.

2. Use PHP to implement database backup

1. Connect to the database

Before using PHP to back up the database, we need to connect to the database first. You can use mysqli or PDO to connect. Assume we use mysqli to connect to the database:

$mysqli = new mysqli(DB_HOST, DB_USER, DB_PASS, DB_NAME);
if($mysqli->connect_errno)
{
    die("Failed to connect: " . $mysqli->connect_error);
}

In the code, DB_HOST, DB_USER, DB_PASS and DB_NAME represent the host name, user name, password and database name of the database respectively. If the connection is successful, the mysqli object will be returned for subsequent operations.

2. Get all the tables in the database

To back up the entire database, we need to get all the tables first. This can be achieved through the following code:

$tables = array();  
$result = $mysqli->query('SHOW TABLES');
while($row = $result->fetch_row())  
{  
     $tables[] = $row[0];  
}

The code uses the mysqli object to execute the SHOW TABLES command to obtain all table names.

3. Back up the table structure and data

It is very important to back up the table structure and data. The backup table structure can be easily used during data recovery. Backing up data ensures data integrity. The following is the code to back up the table structure and data:

foreach($tables as $table)  
{  
    $result = $mysqli->query('SELECT * FROM '.$table);  
    $num_fields = $result->field_count;  
 
    $return .= 'DROP TABLE IF EXISTS '.$table.';';  
    $row2 = $mysqli->query('SHOW CREATE TABLE '.$table)->fetch_row();  
    $return .= "

".$row2[1].";

";  
 
    for($i = 0; $i < $num_fields; $i++)  
    {  
        while($row = $result->fetch_row())  
        {  
            $return .= 'INSERT INTO '.$table.' VALUES(';  
            for($j=0; $j<$num_fields; $j++)  
            {  
                $row[$j] = addslashes($row[$j]);  
                $row[$j] = str_replace("
","\n",$row[$j]);  
                if (isset($row[$j])) { $return .= '"'.$row[$j].'"' ; } else { $return .= '""'; }  
                if ($j<($num_fields-1)) { $return.= ','; }  
            }  
            $return .= ");
";  
        }  
    }  
    $return .= "


";  
}

This code will traverse all tables and execute SHOW CREATE TABLE to generate table structure definitions for each table. Next, you will use the INSERT INTO command to insert the data in the table into the backup file. Because the data comes in many different formats, it needs to be escaped.

4. Write to the backup file

Now that we have obtained all the tables and data, we will write them to the backup file. The following is the code to write backup data to a file:

$backup_file = './backup/'.DB_NAME.'_'.date("Y-M-d").'_'.time().'.sql';  
$fh = fopen($backup_file, 'w');  
fwrite($fh, $return);  
fclose($fh);  

The code creates a backup file and writes the backup content to the file. The backup file is named with the database name, backup date and time.

3. Implementation of scheduled tasks

1. Using Crontab

Using Crontab is a common way to implement scheduled tasks, and you can easily configure the execution time and execution cycle of the task. . Suppose we need to perform a database backup operation at 12 midnight every day, you can use the following command to add the backup task to Crontab:

crontab -e

Then add the following command:

0 0 * * * /usr/bin/php /path/to/backup.php >> /path/to/backup.log

The above command will be executed at midnight every day Execute the backup.php script at 12 o'clock and write the running results to the backup.log file.

2. Use third-party tools

If you don’t want to use Crontab, you can also try to use third-party tools to implement scheduled tasks. For example, tools such as PHP Task Scheduler and CronManager can be used to manage scheduled tasks without requiring any configuration changes to the server.

4. Summary

Backing up data is an important part of ensuring the security of corporate assets. This article introduces the method of using PHP to write database backup, which can help administrators automatically perform data backup and reduce their workload. Finally, no matter which method you choose, be sure to back up your data in a timely manner to ensure data security.

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