public function assertInstalled()
{
if ($this->installed) {
return;
}
try {
$sql = "SELECT value FROM {$this->table_prefix}config WHERE name = 'installed'";
$this->getConnection('read')->query($sql);
} catch (\DatabaseException $e) {
throw new \InstallationException("Unable to handle this request. This site is not configured or the database is down.");
}
$this->installed = true;
}