Re: [cx-oracle-users] cx-oracle-users Digest, Vol 66, Issue 4

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On Wed, Dec 7, 2011 at 6:08 PM, <
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> Today's Topics:
>
>   1. SessionPool and DRCP (Arshavir Grigorian)
>   2. Passing None as values of bind variables in cx_Oracle's
>      cursor.execute() command (Wong Wah Meng-R32813)
>   3. Re: Passing None as values of bind variables in cx_Oracle's
>      cursor.execute() command (Amaury Forgeot d'Arc)
>   4. Re: Passing None as values of bind variables in cx_Oracle's
>      cursor.execute() command (Wong Wah Meng-R32813)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 6 Dec 2011 19:53:43 -0800
> From: Arshavir Grigorian <gri...@gm...>
> Subject: [cx-oracle-users] SessionPool and DRCP
> To: cx-...@li...
> Message-ID:
>        <CACdn6enT8--t2SPwbqMJTtHJRriYC-0bD2SZugk+E=vOf...@ma...
> >
> Content-Type: text/plain; charset=ISO-8859-1
>
> Hi, can someone please explain the relationship between SessionPool
> and DRCP? Do they work together or is DRCP supposed to replace
> SessionPool? Thanks.
>
>
> As indicated in the OCI doc,
http://docs.oracle.com/cd/E11882_01/appdev.112/e10646.pdf
Session pooling can be instructed to allocate sessions from DRCP.

Kuassi Mensah

http://db360.blogspot.com


> ------------------------------
>
> Message: 2
> Date: Wed, 7 Dec 2011 10:15:27 +0000
> From: Wong Wah Meng-R32813 <r3...@fr...>
> Subject: [cx-oracle-users] Passing None as values of bind variables in
>        cx_Oracle's cursor.execute() command
> To: "cx-...@li..."
>        <cx-...@li...>
> Message-ID:
>        <
> 02E...@03...>
>
> Content-Type: text/plain; charset="us-ascii"
>
> Hello there,
>
> I am converting my application from python 1.5.2 and oracledb to python
> 2.7.1 and cx_Oracle..
>
> I noticed one issue here whenever the bind variable's value is None, it
> exhibits some strange behavior.
>
> First observation: When it is the first time I pass in a bind variable as
> None, it gives an EOL file. However, subsequent passing of None value to
> the same SQL seems to be working fine.
>
> Second observation: When there is more than one bind variables contain
> None value, the value that actually got received at Oracle level seems to
> be messed up. (We turn on the highest debug level at Oracle level in order
> to see the bind variable value that are received). Those defined as None
> are received as some arbitrary value, some are the values from one or a few
> of the total bind variables.
>
> I read something about passing None is not supported in cx_Oracle, is it
> true and is there a workaround? I think the second observation could be due
> to the buffer is not flushed from a previous usage and still being used in
> the subsequent call.
>
> Is there anyway we can get rid of both observation? Must we remove any
> bind variables that we know carrying None as value in the SQL statement?
> This looks like some extensive change if our application needs to verify
> the value first before it being used in the SQL.
>
>
>
> Regards,
> Wah Meng
> Goto http://cimhelp.freescale.net to create a Genesis Wafermap Ticket.
>
> -------------- next part --------------
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> ------------------------------
>
> Message: 3
> Date: Wed, 7 Dec 2011 11:27:36 +0100
> From: "Amaury Forgeot d'Arc" <ama...@gm...>
> Subject: Re: [cx-oracle-users] Passing None as values of bind
>        variables in cx_Oracle's cursor.execute() command
> To: cx-...@li...
> Message-ID:
>        <CAGmFidbhf7WazwtfKq9g26Yx2xk7HAmhG2zvry=VXX...@ma...
> >
> Content-Type: text/plain; charset="windows-1252"
>
> Hi,
>
> 2011/12/7 Wong Wah Meng-R32813 <r3...@fr...>
>
> >  Hello there,****
> >
> > ** **
> >
> > I am converting my application from python 1.5.2 and oracledb to python
> > 2.7.1 and cx_Oracle.. ****
> >
> > ** **
> >
> > I noticed one issue here whenever the bind variable?s value is None, it
> > exhibits some strange behavior.****
> >
> > ** **
> >
> > First observation: When it is the first time I pass in a bind variable as
> > None, it gives an EOL file. However, subsequent passing of None value to
> > the same SQL seems to be working fine.
> >
>
> This is surprising. But what do you mean by "EOL file"?
>
>
> > Second observation: When there is more than one bind variables contain
> > None value, the value that actually got received at Oracle level seems to
> > be messed up. (We turn on the highest debug level at Oracle level in
> order
> > to see the bind variable value that are received). Those defined as None
> > are received as some arbitrary value, some are the values from one or a
> few
> > of the total bind variables.
> >
>
> When None is passed, cx_Oracle sets the "NULL indicator" of the bind
> variable. But this changes only one bit of the memory, so if you look at
> the raw memory, it will indeed contain random data except for the "NULL
> indicator" bit.
>
>
> > I read something about passing None is not supported in cx_Oracle, is it
> > true and is there a workaround? I think the second observation could be
> due
> > to the buffer is not flushed from a previous usage and still being used
> in
> > the subsequent call. ****
> >
> > ** **
> >
> > Is there anyway we can get rid of both observation? Must we remove any
> > bind variables that we know carrying None as value in the SQL statement?
> > This looks like some extensive change if our application needs to verify
> > the value first before it being used in the SQL.
> >
>
> The None value *is* supported. There used to be an issue when
> cursor.executemany() determines the type of a variable, when the first
> value for this variable is a None and following values are numbers.
> But this caused an explicit conversion error, and it has been fixed some
> releases ago anyway.
>
> Could you show us a test script that reproduces your problem?
>
> --
> Amaury Forgeot d'Arc
> -------------- next part --------------
> An HTML attachment was scrubbed...
>
> ------------------------------
>
> Message: 4
> Date: Thu, 8 Dec 2011 02:08:00 +0000
> From: Wong Wah Meng-R32813 <r3...@fr...>
> Subject: Re: [cx-oracle-users] Passing None as values of bind
>        variables in cx_Oracle's cursor.execute() command
> To: "cx-...@li..."
>        <cx-...@li...>
> Message-ID:
>        <
> 78E...@03...>
>
> Content-Type: text/plain; charset="us-ascii"
>
> Thanks for your reply. Based on your None as bind variable's value *is*
> supported, I would like to redo my testing to reaffirm the case before
> updating you my test script. Maybe something was introduced in my
> inputtypehandler of the cursor object. I will revert with my findings later.
>
> From: Amaury Forgeot d'Arc [mailto:ama...@gm...]
> Sent: Wednesday, December 07, 2011 6:28 PM
> To: cx-...@li...
> Subject: Re: [cx-oracle-users] Passing None as values of bind variables in
> cx_Oracle's cursor.execute() command
>
> Hi,
> 2011/12/7 Wong Wah Meng-R32813 <r3...@fr...<mailto:
> r3...@fr...>>
> Hello there,
>
> I am converting my application from python 1.5.2 and oracledb to python
> 2.7.1 and cx_Oracle..
>
> I noticed one issue here whenever the bind variable's value is None, it
> exhibits some strange behavior.
>
> First observation: When it is the first time I pass in a bind variable as
> None, it gives an EOL file. However, subsequent passing of None value to
> the same SQL seems to be working fine.
>
> This is surprising. But what do you mean by "EOL file"?
>
> Second observation: When there is more than one bind variables contain
> None value, the value that actually got received at Oracle level seems to
> be messed up. (We turn on the highest debug level at Oracle level in order
> to see the bind variable value that are received). Those defined as None
> are received as some arbitrary value, some are the values from one or a few
> of the total bind variables.
>
> When None is passed, cx_Oracle sets the "NULL indicator" of the bind
> variable. But this changes only one bit of the memory, so if you look at
> the raw memory, it will indeed contain random data except for the "NULL
> indicator" bit.
>
> I read something about passing None is not supported in cx_Oracle, is it
> true and is there a workaround? I think the second observation could be due
> to the buffer is not flushed from a previous usage and still being used in
> the subsequent call.
>
> Is there anyway we can get rid of both observation? Must we remove any
> bind variables that we know carrying None as value in the SQL statement?
> This looks like some extensive change if our application needs to verify
> the value first before it being used in the SQL.
>
> The None value *is* supported. There used to be an issue when
> cursor.executemany() determines the type of a variable, when the first
> value for this variable is a None and following values are numbers.
> But this caused an explicit conversion error, and it has been fixed some
> releases ago anyway.
>
> Could you show us a test script that reproduces your problem?
>
> --
> Amaury Forgeot d'Arc
> -------------- next part --------------
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> End of cx-oracle-users Digest, Vol 66, Issue 4
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-- 
Kuassi
- book http://www.amazon.com/exec/obidos/ASIN/1555583296