How do I set up an engine so that Oracle Number fields are not
converted to Decimal?
I'm dealing with a bunch of code with hand-rolled SQL query strings,
and as the first step was going to use connections from SqlAlchemy's
connection pool, as I change the queries one-by-one. The only problem
is that our main queries get 500 Number columns and SqlAlchemy is
converting them to Decimals, slowing the queries down by a factor of
10.
Here's an example
>>> engine = sqlalchemy.create_engine("oracle+cx_oracle://"+connString)
>>> conn = engine.pool.connect()
>>> cursor = conn.cursor()
>>> cursor.execute("""SELECT * FROM MY_TABLE""")
>>> r = cursor.fetchone()
>>> r[-1]
Decimal('0.878935370620606')
The conversion is done via the outputtypehandler of the connection
object. I can circumvent it by either setting
>>> cursor.connection.outputtypehandler = None
or
>>> cursor.outputtypehandler = lambda *args : None
but is there a better, more standard way to convert the Numbers to
floats and not Decimals for arbitrary queries?
(Setting engine.dialect.supports_native_decimal to False doesn't work.
I believe the dialect is creating the output type handler before any
connection is opened.)
--
--Anthony
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