(PHP 7 >= 7.4.0, PHP 8)
SQLite3::backup — Backup one database to another database
$destination, string $sourceDatabase = "main", string $destinationDatabase = "main"): boolSQLite3::backup() copies the contents of one database into another, overwriting the contents of the destination database. It is useful either for creating backups of databases or for copying in-memory databases to or from persistent files.
    As of SQLite 3.27.0 (2019-02-07), it is also possible to use the statement
    VACUUM INTO 'file.db'; to backup the database to a new file.
   
destinationA database connection opened with SQLite3::open().
sourceDatabase
      The database name is "main" for the main database,
      "temp" for the temporary database,
      or the name specified after the AS keyword
      in an ATTACH statement for an attached database.
     
destinationDatabase
      Analogous to sourceDatabase
      but for the destination.
     
   Returns true on success or false on failure.
  
Example #1 Backup an existing database
<?php
// $conn is a connection to an already opened sqlite3 database
$backup = new SQLite3('backup.sqlite');
$conn->backup($backup);
?>