group_export.to_sql(con = db, name = config.table_group_export, if_exists = 'replace', flavor = 'mysql', index = False)

engine = sa.create_engine('postgresql:///somedb')
pandas_sql = pd.io.sql.pandasSQL_builder(engine, schema=None, flavor=None)

def to_sql_k(self, frame, name, if_exists='fail', index=True,
           index_label=None, schema=None, chunksize=None, dtype=None, **kwargs):
    if dtype is not None:
        from sqlalchemy.types import to_instance, TypeEngine
        for col, my_type in dtype.items():
            if not isinstance(to_instance(my_type), TypeEngine):
                raise ValueError('The type of %s is not a SQLAlchemy '
                                 'type ' % col)

    table = pd.io.sql.SQLTable(name, self, frame=frame, index=index,
                     if_exists=if_exists, index_label=index_label,
                     schema=schema, dtype=dtype, **kwargs)
    table.create()
    table.insert(chunksize)

to_sql_k(pandas_sql, df2save, 'tmp',
        index=True, index_label='id', keys='id', if_exists='replace')

CREATE TABLE public.tmp
(
  id bigint NOT NULL DEFAULT nextval('tmp_id_seq'::regclass),
...
)

metadata = MetaData()
metadata.reflect(db.engine, only=tableNamesDict.values())
Base = automap_base(metadata=metadata)
Base.prepare()

for df in dfs.keys():
    cols = dfs[df].columns
    cols = [str(col) for col in cols if 'id' in col.lower()]
    schema = pd.io.sql.get_schema(dfs[df],df, con=db.engine, keys=cols)
    db.engine.execute('DROP TABLE ' + df + ';')
    db.engine.execute(schema)
    dfs[df].to_sql(df,con=db.engine, index=False, if_exists='append')

alchemyClassDict = {}
for t in Base.classes.keys():
    alchemyClassDict[t] = Base.classes[t]

res = db.session.query(alchemyClassDict['user']).first()