>
> OK, is “cancellation_obj” a column object with CLOB as the datatype ?
>
Yes, that's how it's defined in the database.
Because of dynamic nature of the code, I was using append_column without
specifying column type. I made changes to define column in
table.c.<column_name> format rather than just using Column('column name').
This way, I can make sure column data types are included with column
definitions, without me having to specify the data type explicitly with
each column.
It's interesting that I used that one way (out of three possible ways) that
wasn't 'right', but it's all good now :)
Now onto changing from fetchmany() to fetchone() - since LOBs are pretty
much forcing me to use fetchone().
Thank you for your help!
GP
On Monday, March 16, 2015 at 5:54:54 PM UTC-4, Michael Bayer wrote:
>
>
>
> GP <[email protected] <javascript:>> wrote:
>
> > So that's what was happening:
> >
> > This select construct fails:
> > select_query = select()
> > select_query.append_column(contract_id)
> > select_query.append_column(cancel_dt)
> > select_query.append_column(cancellation_obj)
> > select_query.append_from(source_table_name)
> >
> >
> > But this select construct works:
> > select_query = select([source_table.c.contract_id,
> source_table.c.cancel_dt, source_table.c.cancellation_quote_obj])
> >
> > So it's just matter of rewriting select query in the 'right' way.
> >
> > Thanks for pointing in the right direction!
>
> OK, is “cancellation_obj” a column object with CLOB as the datatype ?
>
> even if you just made it this:
>
> from sqlalchemy.sql import column
> append_column(column(‘cancellation_obj’, CLOB))
>
> that should work.
>
>
> otherwise, what’s interesting here is to add a “column” without a datatype
> both bypasses the usual Table metadata feature, but also, bypasses if it
> was totally a plain text SQL string there’s logic in place to intercept the
> CLOB in that case also. the recipe above managed to avoid both.
>
>
>
> > GP
> >
> > On Monday, March 16, 2015 at 4:57:28 PM UTC-4, GP wrote:
> > I think now I (probably) know where this may be coming from.
> >
> > You asked
> > > is the original query a plain string and not a Core SQL expression
> >
> > The way I am forming the query is by using select , append_column,
> append_whereclause and finally append_from('my_table'). I think this pretty
> much generates a plain string query and not the one that's tied to a
> sqlalchemy table type object. And this may be why sqlalchemy is not
> applying necessary conversion because it doesn't really know the data types
> of the columns I am selecting?
> >
> > Apologies if I am simplifying this too much and/or talking nonsense.
> >
> > Thanks
> > GP
> >
> > On Monday, March 16, 2015 at 3:49:32 PM UTC-4, GP wrote:
> > Thank you Michael.
> >
> > auto_covert_lobs : I ran with all three possible values: True, False,
> and without supplying it. The results are the same.
> >
> > The original query is a bit more complicated than the example I gave,
> and is built dynamically. But I am using sqlalchemy select, and not a plain
> string. Query is of object type "sqlalchemy.select.sql.selectable.Select"
> (Or "sqlalchemy.sql.expression.Select"?), if it helps.
> >
> > Here is what the query object value looks like:
> > SELECT CAST(contract_id AS FLOAT) AS contract_id, cancel_dt AS
> cancel_dt, cancellation_obj AS cancellation_obj FROM contract_cancellation
> WHERE updated_ts BETWEEN :updated_ts_1 AND :updated_ts_2
> >
> > Let me try calling value().
> >
> >
> > Thanks
> > GP
> >
> > --
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