pg8000 adapter doesn't send native Numerics

[Former user]

class _PGNumeric in pg8000.py needs these lines to turn on sending of Numerics:

    def bind_processor(self, dialect):
        return None

psycopg2.py has the same code. If this code is not present, sqltypes.Numeric will force conversion to float instead of passing a decimal.Decimal.

pg8000 1.08 appears to have a bug where it truncates decimals after the decimal point. See also https://github.com/mfenniak/pg8000/issues/7 for this bug.

[Mike Bayer]

the patch as is causes float coercion to fail, in a way that does not occur with psycopg2:

======================================================================
FAIL: test.sql.test_types.NumericTest.test_float_as_decimal
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/nose/case.py", line 187, in runTest
    self.test(*self.arg)
  File "/Users/classic/dev/sqlalchemy/./test/sql/test_types.py", line 1363, in test_float_as_decimal
    filter_ = lambda n:n is not None and round(n, 5) or None
  File "<string>", line 1, in <lambda>
  File "/Users/classic/dev/sqlalchemy/./test/lib/testing.py", line 340, in decorate
    return fn(*args, **kw)
  File "/Users/classic/dev/sqlalchemy/./test/sql/test_types.py", line 1336, in _do_test
    eq_(result, output)
  File "/Users/classic/dev/sqlalchemy/./test/lib/testing.py", line 499, in eq_
    assert a == b, msg or "%r != %r" % (a, b)
AssertionError: set([15.7563, None](16.0,)) != set([None](15.7563,))

======================================================================
FAIL: test.sql.test_types.NumericTest.test_float_as_float
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/nose/case.py", line 187, in runTest
    self.test(*self.arg)
  File "/Users/classic/dev/sqlalchemy/./test/sql/test_types.py", line 1371, in test_float_as_float
    filter_ = lambda n:n is not None and round(n, 5) or None
  File "<string>", line 1, in <lambda>
  File "/Users/classic/dev/sqlalchemy/./test/lib/testing.py", line 340, in decorate
    return fn(*args, **kw)
  File "/Users/classic/dev/sqlalchemy/./test/sql/test_types.py", line 1336, in _do_test
    eq_(result, output)
  File "/Users/classic/dev/sqlalchemy/./test/lib/testing.py", line 499, in eq_
    assert a == b, msg or "%r != %r" % (a, b)
AssertionError: set([15.7563](16.0,)) != set([15.7563](15.7563))

----------------------------------------------------------------------

an adjustment is to disable bind processing for Numeric but not Float. I have a patch here that accomplishes that.

[Mike Bayer]

f9113b5dbfe5fec59759b1018465e729f6741167 adds an exception for when FLOAT is used. pg8000 is sensitive to the declared type in the database so this approach seems to cover all the bases. Thanks for the patch !

[Mike Bayer]

Removing milestone: 0.7.0 (automated comment)