How to implement incremental backup of database backup in PHP

As the data stored in the database increases, it becomes very important to back up the data. There are two types of backup, full backup and incremental backup. A full backup backs up the entire database to another location, while an incremental backup backs up only the data that has changed since the last backup. For large databases, incremental backup can greatly reduce backup time and storage space.

In PHP, we can use the following steps to achieve incremental backup of the database:

1. Connect to the database

Connect to the database using PHP and select The database to be backed up. We can use mysqli or PDO to achieve this step.

$db = new mysqli('localhost', 'username', 'password', 'database_name');

or

$db = new PDO('mysql:host=localhost;dbname=database_name', 'username', 'password');

2. Get the last backup time

In incremental backup, we need to get the time of the last backup so that we can only backup Data modified since then. We can get the last backup time from a log file or a backup record table.

$last_backup_time = file_get_contents('/path/to/last_backup_time.txt');

or

$stmt = $db->prepare("SELECT date FROM backup_logs ORDER BY date DESC LIMIT 1"); $stmt->execute(); $last_backup_time = $stmt->fetchColumn();

3. Get modified data

Use SQL query statements to obtain modified or new data since the last backup time.

$sql = "SELECT * FROM table_name WHERE modify_time > '$last_backup_time'"; $result = $db->query($sql);

4. Back up the modified data to a file

Write the obtained data to a file. Data can be written to files using CSV or SQL format.

$filename = '/path/to/incremental_backup_' . date('YmdHis') . '.csv'; $fp = fopen($filename, 'w'); while ($row = $result->fetch_assoc()) { fputcsv($fp, $row); } fclose($fp);

or

$filename = '/path/to/incremental_backup_' . date('YmdHis') . '.sql'; $fp = fopen($filename, 'w'); while ($row = $result->fetch_assoc()) { // 使用INSERT语句将数据写入文件 $insert = "INSERT INTO table_name (column1, column2, ...) VALUES ('" . implode("', '", $row) . "')"; fwrite($fp, $insert . " "); } fclose($fp);

5. Update the last backup time

After the backup is completed, we need to update the last backup time so that the next backup only Back up data modified since this time.

file_put_contents('/path/to/last_backup_time.txt', date('Y-m-d H:i:s'));

or

$stmt = $db->prepare("INSERT INTO backup_logs (date) VALUES (?)"); $stmt->execute(array(date('Y-m-d H:i:s')));

The above are the basic steps for implementing incremental backup of database backup in PHP. However, one thing we need to pay attention to is that when backing up, the table and data need to be locked to prevent new modifications during the backup from causing the backup to fail. In addition, when backing up data, data integrity and consistency need to be considered. Therefore, it is recommended to use professional backup tools or frameworks in practical applications to maximize data security and backup quality.

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