def Copy(self, old_urn, new_urn, age=NEWEST_TIME, token=None, limit=None,
           sync=False):
    if token is None:
      token = data_store.default_token

    values = {}
    for predicate, value, ts in data_store.DB.ResolvePrefix(
        old_urn, AFF4_PREFIXES,
        timestamp=self.ParseAgeSpecification(age),
        token=token, limit=limit):
      values.setdefault(predicate, []).append((value, ts))

    if values:
      data_store.DB.MultiSet(new_urn, values,
                             token=token, replace=False,
                             sync=sync)
Render the UPDATE..FROM clause specific to MSSQL.
dataset/ETHPy150Open google/grr/grr/lib/aff4.py/Factory.Copy--crossover with--dataset/ETHPy150Open RoseOu/flasky/venv/lib/python2.7/site-packages/sqlalchemy/dialects/mssql/base.py/MSSQLCompiler.update_from_clause