[sqlalchemy] Blob Issue

[dhanil anupurath]

Hi

I am having a trouble with SA-oracle-Blob datatype.
Here I have a test program like this.

import pkg_resources
pkg_resources.require("cx-Oracle>=5.0.3")
import cx_Oracle
import sqlalchemy
from sqlalchemy.sql import select

db=sqlalchemy.create_engine('oracle://cse:cse@localhost')
conn = db.connect()

result=conn.execute(select(["dummy"]))
print "helloooooooooooooo"
print result.fetchone()

conn.close()

cse is the username and password for ORACLE schema

duumy is the table name ,it has a column with datatype BLob.

For this am geting the result with the error,

ORA-00932: inconsistent datatypes: expected NUMBER got BLOB

Is there is any solution so that i do can do more complecated
select statements.

Is Blob not supported for ORACLE-SA

Any help is encouraged.

THANKS

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[Michael Bayer]

cx_oracle requires special type handling with BLOB. You must pass full typing information to SQLAlchemy in order to have them handled directly.

The test case below doesn't make sense to me since "select(["dummy"])" would render "SELECT dummy FROM DUAL", which I didn't think was the same as "select * from dummy".

In any case, if you are using textual SQL and need typing information, use the text() construct, http://www.sqlalchemy.org/docs/reference/sqlalchemy/expressions.html#sqlalchemy.sql.expression.text , specifying typemap and bindparams as appropriate.

text("select * from dummy where foo=:bar", bindparams=[bindparam('bar', type_=String)], typemap={'a':Binary, 'b':String})