diff --git a/zipline/finance/trading.py b/zipline/finance/trading.py
index e6e886d3..f1bdf930 100644
--- a/zipline/finance/trading.py
+++ b/zipline/finance/trading.py
@@ -17,12 +17,10 @@ import bisect
 import logbook
 import datetime
 from functools import wraps
-import sqlite3
 
 import pandas as pd
 import numpy as np
 from sqlalchemy import create_engine
-# from multipledispatch import dispatch
 
 from zipline.data.loader import load_market_data
 from zipline.utils import tradingcalendar
@@ -163,59 +161,83 @@ class TradingEnvironment(object):
                    futures_data={},
                    exchanges_data={},
                    root_symbols_data={},
+                   equities_df=pd.DataFrame(),
+                   futures_df=pd.DataFrame(),
+                   exchanges_df=pd.DataFrame(),
+                   root_symbols_df=pd.DataFrame(),
                    equities_identifiers=[],
                    futures_identifiers=[],
                    exchanges_identifiers=[],
-                   root_symbols_identifiers=[]):
+                   root_symbols_identifiers=[],
+                   allow_sid_assignment=True):
         """ Write the supplied data to the database.
 
         Parameters
         ----------
-        equities_data: dict
+        equities_data: dict, optional
             A dictionary of equity metadata
-        futures_data: dict
+        futures_data: dict, optional
             A dictionary of futures metadata
-        exchanges_data: dict
+        exchanges_data: dict, optional
             A dictionary of exchanges metadata
-        root_symbols_data: dict
+        root_symbols_data: dict, optional
             A dictionary of root symbols metadata
-        equities_identifiers: list
-            A list of equities identifiers (sids or symbols)
-        futures_identifiers: list
-            A list of futures identifiers (sids or symbols)
-        exchanges_identifiers: list
+        equities_df: pandas.DataFrame, optional
+            A pandas.DataFrame of equity metadata
+        futures_df: pandas.DataFrame, optional
+            A pandas.DataFrame of futures metadata
+        exchanges_df: pandas.DataFrame, optional
+            A pandas.DataFrame of exchanges metadata
+        root_symbols_df: pandas.DataFrame, optional
+            A pandas.DataFrame of root symbols metadata
+        equities_identifiers: list, optional
+            A list of equities identifiers (sids, symbols, Assets)
+        futures_identifiers: list, optional
+            A list of futures identifiers (sids, symbols, Assets)
+        exchanges_identifiers: list, optional
             A list of exchanges identifiers (ids or names)
-        root_symbols_identifiers: list
+        root_symbols_identifiers: list, optional
             A list of root symbols identifiers (ids or symbols)
         """
-
         if engine:
             self.engine = engine
 
+        # If any pandas.DataFrame data has been provided,
+        # write it to the database.
+        if not(equities_df.empty and futures_df.empty and
+               exchanges_df.empty and root_symbols_df.empty):
+            self._write_data_dataframes(equities_df, futures_df,
+                                        exchanges_df, root_symbols_df)
+
         if (equities_data or futures_data or exchanges_data or
                 root_symbols_data):
             self._write_data_dicts(equities_data, futures_data,
                                    exchanges_data, root_symbols_data)
 
-        if (equities_identifiers or futures_identifiers or
-                exchanges_identifiers or root_symbols_identifiers):
-            self._write_data_lists(equities_identifiers,
-                                   futures_identifiers,
-                                   exchanges_identifiers,
-                                   root_symbols_identifiers)
+        # These could be lists or other iterables such as a pandas.Index.
+        # For simplicity, don't check whether data has been provided.
+        self._write_data_lists(equities_identifiers,
+                               futures_identifiers,
+                               exchanges_identifiers,
+                               root_symbols_identifiers,
+                               allow_sid_assignment=allow_sid_assignment)
 
     def _write_data_lists(self, equities=[], futures=[],
-                          exchanges=[], root_symbols=[]):
+                          exchanges=[], root_symbols=[],
+                          allow_sid_assignment=True):
         AssetDBWriterFromList(equities, futures, exchanges, root_symbols)\
-            .write_all(self.engine)
+            .write_all(self.engine, allow_sid_assignment=allow_sid_assignment)
 
     def _write_data_dicts(self, equities={}, futures={},
-                          exchanges={}, root_symbols={}):
+                          exchanges={}, root_symbols={},
+                          allow_sid_assignment=True):
         AssetDBWriterFromDictionary(equities, futures, exchanges, root_symbols)\
             .write_all(self.engine)
 
-    def _write_data_dataframes(self, equities, futures,
-                               exchanges, root_symbols):
+    def _write_data_dataframes(self, equities=pd.DataFrame(),
+                               futures=pd.DataFrame(),
+                               exchanges=pd.DataFrame(),
+                               root_symbols=pd.DataFrame()):
         AssetDBWriterFromDataFrame(equities, futures, exchanges, root_symbols)\
             .write_all(self.engine)