/**
* Return the max version number from the DB,
* or "0" in the case of no versions available.
* We must use strings because our date/timestamp
* when treated as an integer would cause overflow.
*
* @return string
*/
public function getMaxVersion()
{
// We only want one row but we cannot assume that we are using MySQL and use a LIMIT statement
// as it is not part of the SQL standard. Thus we have to select all rows and use PHP to return
// the record we need
$versions_nested = $this->_adapter->selectAll(sprintf('SELECT version FROM %s', $this->_adapter->Identifier(PHIGRATE_TS_SCHEMA_TBL_NAME)));
$versions = array();
foreach ($versions_nested as $v) {
$versions[] = $v['version'];
}
$num_versions = count($versions);
$version = null;
if ($num_versions) {
sort($versions);
//sorts lowest-to-highest (ascending)
$version = (string) $versions[$num_versions - 1];
}
return $version;
}