function get_primary_key($table_name = null)
{
// let's see what the parent can do
$primary_key = parent::get_primary_key($table_name);
if ($primary_key !== FALSE) {
return $primary_key;
}
// set default value for table_name if not set.
if (!isset($table_name)) {
$table_name = $this->table_name;
}
// postgre need this
if ($this->subdriver == 'pgsql') {
$SQL = "SELECT\n pg_attribute.attname\n FROM pg_index, pg_class, pg_attribute\n WHERE\n pg_class.oid = '" . $table_name . "'::regclass AND\n indrelid = pg_class.oid AND\n pg_attribute.attrelid = pg_class.oid AND\n pg_attribute.attnum = any(pg_index.indkey);";
$query = $this->db->query($SQL);
$row = $query->row();
$primary_key = $row->attname;
}
return $primary_key;
}
