made reflect metadata a flag (fixes #9)

dataset/__init__.py

@@ -7,16 +7,19 @@ from dataset.persistence.database import Database
 from dataset.persistence.table import Table
 from dataset.freeze.app import freeze
 
-def connect(url):
+__all__ = ['Database', 'Table', 'freeze', 'connect']
+
+
+def connect(url, reflectMetadata=True):
     """
     Opens a new connection to a database. *url* can be any valid `SQLAlchemy engine URL`_. Returns
-    an instance of :py:class:`Database <dataset.Database>`.
+    an instance of :py:class:`Database <dataset.Database>`. Set *reflectMetadata* to False if you
+    don't want the entire database schema to be pre-loaded. This significantly speeds up
+    connecting to large databases with lots of tables.
     ::
 
         db = dataset.connect('sqlite:///factbook.db')
 
     .. _SQLAlchemy Engine URL: http://docs.sqlalchemy.org/en/latest/core/engines.html#sqlalchemy.create_engine
     """
-    return Database(url)
-
-
+    return Database(url, reflectMetadata)

dataset/persistence/database.py

@@ -17,7 +17,7 @@ log = logging.getLogger(__name__)
 
 class Database(object):
 
-    def __init__(self, url):
+    def __init__(self, url, reflectMetadata=True):
         kw = {}
         if url.startswith('postgres'):
             kw['poolclass'] = NullPool
@@ -27,6 +27,7 @@ class Database(object):
         self.engine = construct_engine(engine)
         self.metadata = MetaData()
         self.metadata.bind = self.engine
+        if reflectMetadata:
             self.metadata.reflect(self.engine)
         self._tables = {}
 

setup.py

@@ -2,7 +2,7 @@ from setuptools import setup, find_packages
 
 setup(
     name='dataset',
-    version='0.3.3',
+    version='0.3.4',
     description="Toolkit for Python-based data processing.",
     long_description="",
     classifiers=[