getAttachedDatabases example

/** * {@inheritdoc} */
  public function findTables($table_expression) {
    $tables = [];

    // The SQLite implementation doesn't need to use the same filtering strategy     // as the parent one because individually prefixed tables live in their own     // schema (database), which means that neither the main database nor any     // attached one will contain a prefixed table name, so we just need to loop     // over all known schemas and filter by the user-supplied table expression.     $attached_dbs = $this->connection->getAttachedDatabases();
    foreach ($attached_dbs as $schema) {
      // Can't use query placeholders for the schema because the query would       // have to be :prefixsqlite_master, which does not work. We also need to       // ignore the internal SQLite tables.       $result = $this->connection->query("SELECT name FROM [" . $schema . "].sqlite_master WHERE type = :type AND name LIKE :table_name AND name NOT LIKE :pattern", [
        ':type' => 'table',
        ':table_name' => $table_expression,
        ':pattern' => 'sqlite_%',
      ]);
      $tables += $result->fetchAllKeyed(0, 0);
    }