remove "native decimal" warning

Removed the warning that emits from the :class:`_types.Numeric` type about
DBAPIs not supporting Decimal values natively. This warning was oriented
towards SQLite, which does not have any real way without additional
extensions or workarounds of handling precision numeric values more than 15
significant digits as it only uses floating point math to represent
numbers. As this is a known and documented limitation in SQLite itself, and
not a quirk of the pysqlite driver, there's no need for SQLAlchemy to warn
for this. The change does not otherwise modify how precision numerics are
handled. Values can continue to be handled as ``Decimal()`` or ``float()``
as configured with the :class:`_types.Numeric`, :class:`_types.Float` , and
related datatypes, just without the ability to maintain precision beyond 15
significant digits when using SQLite, unless alternate representations such
as strings are used.

Fixes: #7299
Change-Id: Ic570f8107177dec3ddbe94c7b43f40057b03276a

1 files changed, 15 insertions, 0 deletions

diff --git a/lib/sqlalchemy/testing/requirements.py b/lib/sqlalchemy/testing/requirements.py
index 4cc431bb7..56df452a5 100644
--- a/lib/sqlalchemy/testing/requirements.py
+++ b/lib/sqlalchemy/testing/requirements.py
@@ -957,6 +957,21 @@ class SuiteRequirements(Requirements):
         return exclusions.open()
 
     @property
+    def numeric_received_as_decimal_untyped(self):
+        """target backend will return result columns that are explicitly
+        against NUMERIC or similar precision-numeric datatypes (not including
+        FLOAT or INT types) as Python Decimal objects, and not as floats
+        or ints, including when no SQLAlchemy-side typing information is
+        associated with the statement (e.g. such as a raw SQL string).
+
+        This should be enabled if either the DBAPI itself returns Decimal
+        objects, or if the dialect has set up DBAPI-specific return type
+        handlers such that Decimal objects come back automatically.
+
+        """
+        return exclusions.open()
+
+    @property
     def nested_aggregates(self):
         """target database can select an aggregate from a subquery that's
         also using an aggregate