How to Backup MySQL Database using PHP

Dynamically creating database backup via program will be hand in many a situations. We can schedule the backup process periodically by using CRON jobs. Taking the database backup using PHP programming is easy. In this tutorial, we are going to learn how to backup MySQL database with a simple core PHP code.

data-backup

First, I get the database connection object to get the table schema and data to be dumped into a file. I read all the table names from the database and store into an array. Then, I iterate the array of database tables to prepare the SQL script for the data/structure. This SQL script will be written into a file which will be downloaded to the user’s browser and removed from the target.

Getting Database Table Names

The code shows how to get the database connection and set the default character set before executing queries. Since we are dumping the database structure and the data, we need to be careful about the consistency.  By setting the default character set, it tells the database server about the character encoding.

The SHOW TABLES statement is used to fetch the table names. The table names are stored in an array which will be iterated to prepare the backup SQL script for the database structure and the data.

<?php
// Database configuration
$host = "localhost";
$username = "root";
$password = "test";
$database_name = "star_rating";

// Get connection object and set the charset
$conn = mysqli_connect($host, $username, $password, $database_name);
$conn->set_charset("utf8");


// Get All Table Names From the Database
$tables = array();
$sql = "SHOW TABLES";
$result = mysqli_query($conn, $sql);

while ($row = mysqli_fetch_row($result)) {
    $tables[] = $row[0];
}
?>

Create SQL Script for Table Data/Structure

After fetching the list of database table name in an array, I loop through this array to generate the SQL script. For each loop iteration, I have generated the SQL script for creating the table structure and dumping data into the table. The SHOW CREATE TABLE statement is used to get the SQL for creating a table structure. Then, I get the column name and data to prepare the SQL for dumping data.

<?php
$sqlScript = "";
foreach ($tables as $table) {
    
    // Prepare SQLscript for creating table structure
    $query = "SHOW CREATE TABLE $table";
    $result = mysqli_query($conn, $query);
    $row = mysqli_fetch_row($result);
    
    $sqlScript .= "\n\n" . $row[1] . ";\n\n";
    
    
    $query = "SELECT * FROM $table";
    $result = mysqli_query($conn, $query);
    
    $columnCount = mysqli_num_fields($result);
    
    // Prepare SQLscript for dumping data for each table
    for ($i = 0; $i < $columnCount; $i ++) {
        while ($row = mysqli_fetch_row($result)) {
            $sqlScript .= "INSERT INTO $table VALUES(";
            for ($j = 0; $j < $columnCount; $j ++) {
                $row[$j] = $row[$j];
                
                if (isset($row[$j])) {
                    $sqlScript .= '"' . $row[$j] . '"';
                } else {
                    $sqlScript .= '""';
                }
                if ($j < ($columnCount - 1)) {
                    $sqlScript .= ',';
                }
            }
            $sqlScript .= ");\n";
        }
    }
    
    $sqlScript .= "\n"; 
}
?>

Save and Download Database Backup File

After preparing the SQL script for the database table and the structure, it will be written into a backup file which is created dynamically in the specified target. Then, this file will be downloaded to the user’s browser and removed from the target location. The code for saving and downloading the database backup file is,

<?php
if(!empty($sqlScript))
{
    // Save the SQL script to a backup file
    $backup_file_name = $database_name . '_backup_' . time() . '.sql';
    $fileHandler = fopen($backup_file_name, 'w+');
    $number_of_lines = fwrite($fileHandler, $sqlScript);
    fclose($fileHandler); 

    // Download the SQL backup file to the browser
    header('Content-Description: File Transfer');
    header('Content-Type: application/octet-stream');
    header('Content-Disposition: attachment; filename=' . basename($backup_file_name));
    header('Content-Transfer-Encoding: binary');
    header('Expires: 0');
    header('Cache-Control: must-revalidate');
    header('Pragma: public');
    header('Content-Length: ' . filesize($backup_file_name));
    ob_clean();
    flush();
    readfile($backup_file_name);
    exec('rm ' . $backup_file_name); 
}
?>

Download

This PHP code tutorial was published on January 24, 2018.

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