On Fri, Jul 24, 2009 at 12:31:02PM +1200, Aaron Robinson wrote:
> if I set the value of a blob column by setting a
> varialbe on my object, it gets written to the db just fine, but when I do it
> inside a transaction using sqlbuilder I have the error. Please see the code
> below.
> 
> Test Code:
> 
> from sqlobject import *
> from array import *
> 
> sqlhub.processConnection = connectionForURI('postgres://user:p...@localhost
> /mydb')
> 
> class MyObject(SQLObject):
>     myInt =  IntCol(default=42)
>     myBlob = BLOBCol(default=None)
> 
> MyObject.createTable()
> 
> #This works:
> myObject = MyObject()
> myObject.myInt = 43
> myObject.myBlob = array('H',range(256)).tostring()

   I hope you know you can set many values at once:
myObject.set(myInt=43, myBlob=array('H',range(256)).tostring())
   (That's offtopic, just a reminder.)

> #This doesn't work:
> record = {'my_int':44, 'my_blob':array('H',range(256)).tostring()}
> conn = sqlhub.getConnection()
> tx = conn.transaction()
> tx.query(conn.sqlrepr(sqlbuilder.Insert(MyObject, [record])))
> tx.commit()
> 
> #psycopg2.DataError: invalid byte sequence for encoding "UTF8": 0x80
> #HINT:  This error can also happen if the byte sequence does not match the
> encoding expected by the server, which is controlled by "client_encoding".

   First, this has nothing with transactions. You can do conn.query() here.
Second, SQLBuilder... SQLObject is a high-level object that does a lot of
things internally, but SQLBuilder is a low-level interface that knows
nothing about classes, columns, column types, conversion; the first
parameters should be string (table name), the values must be converted to
the DB format; for a BLOB it means you have to use psycopg.Binary wrapper.
   This code works for my in Postgres and SQLite:

record = {'my_int':44, 
'my_blob':conn.createBinary(array('H',range(256)).tostring())}
conn.query(conn.sqlrepr(sqlbuilder.Insert(MyObject.sqlmeta.table, [record])))

Oleg.
-- 
     Oleg Broytmann            http://phd.pp.ru/            p...@phd.pp.ru
           Programmers don't die, they just GOSUB without RETURN.

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