SQLite dialect - support relection from affinitypr/65

SQLite allows column types that aren't technically understood in sqlite
by using 'data affinity', which is an algorithm for converting column
types in to some sort of useful type that can be stored and retrieved
from the db. Unfortunatly, this breaks reflection since we (previously)
expected a sqlite db to reflect column types that we permit in the
`ischema_names` for that dialect.

This patch changes the logic for 'unknown' column types during
reflection to instead run through SQLite's data affinity algorithm, and
assigns appropriate types from that.

It also expands the matching for column type to include column types
with spaces (strongly discouraged but allowed by sqlite) and also
completely empty column types (in which case the NullType is assigned,
which sqlite will treat as a Blob - or rather, Blob is treated as
NullType). These changes mean that SQLite will never raise an error for
an unknown type during reflection - there will always be some 'useful'
type returned, which follows the spirit of SQLite (accomodation before
sanity!).

1 files changed, 8 insertions, 2 deletions

diff --git a/test/engine/test_reflection.py b/test/engine/test_reflection.py
index 2f311f7e7..5ba3cac1b 100644
--- a/test/engine/test_reflection.py
+++ b/test/engine/test_reflection.py
@@ -4,8 +4,8 @@ import unicodedata
 import sqlalchemy as sa
 from sqlalchemy import schema, events, event, inspect
 from sqlalchemy import MetaData, Integer, String
-from sqlalchemy.testing import ComparesTables, \
-                            engines, AssertsCompiledSQL, fixtures
+from sqlalchemy.testing import (ComparesTables, engines, AssertsCompiledSQL,
+    fixtures, skip)
 from sqlalchemy.testing.schema import Table, Column
 from sqlalchemy.testing import eq_, assert_raises, assert_raises_message
 from sqlalchemy import testing
@@ -317,8 +317,14 @@ class ReflectionTest(fixtures.TestBase, ComparesTables):
         t2a = Table('test2', m2, autoload=True)
         assert t2a._autoincrement_column is t2a.c.id2
 
+    @skip('sqlite')
     @testing.provide_metadata
     def test_unknown_types(self):
+        """Test the handling of unknown types for the given dialect.
+
+        sqlite is skipped because it has special rules for unknown types using
+        'affinity types' - this feature is tested in that dialect's test spec.
+        """
         meta = self.metadata
         t = Table("test", meta,
             Column('foo', sa.DateTime))