Обсуждение: Using ODBC and VBA to pull data from a large object

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Using ODBC and VBA to pull data from a large object

От
Adam C Falkenberg
Дата:
Good Morning,

I had a question about using ODBC with large objects.  When I query the pg_largeobject table and return data to an ADO recordset, I can only get the first 255 bytes even though the record contains 2048 bytes of data (all the bytes after the first 255 show as 0).  When I checked the type of the record, it was a VarBinary.  Is there a way to have all of the data returned to the recordset?  Thanks for any help.

Adam

Re: Using ODBC and VBA to pull data from a large object

От
Bret Stern
Дата:
On Tue, 2013-09-17 at 08:32 -0400, Adam C Falkenberg wrote:
> Good Morning,
>
> I had a question about using ODBC with large objects.  When I query
> the pg_largeobject table and return data to an ADO recordset, I can
> only get the first 255 bytes even though the record contains 2048
> bytes of data (all the bytes after the first 255 show as 0).  When I
> checked the type of the record, it was a VarBinary.  Is there a way to
> have all of the data returned to the recordset?  Thanks for any help.
>
> Adam


Microsofts sample
http://support.microsoft.com/kb/258038



Re: Using ODBC and VBA to pull data from a large object

От
Adam C Falkenberg
Дата:
Thanks for the response.  The example you sent is what I tried to follow when I originally worked on this.  It works great for the first 255 bytes, but after that it returns 0's.  Is there any way to get all of the data in a large object returned to a recordset (not just the first 255 bytes)?  Thanks again.

Adam C. Falkenberg
Quality Engineer
Great Lakes Works
Phone:  (313) 749 - 3758
Cell:       (313) 910 - 3195




From:        Bret Stern <bret_stern@machinemanagement.com>
To:        Adam C Falkenberg <ACFalkenberg@uss.com>,
Cc:        pgsql-general@postgresql.org
Date:        09/17/2013 10:06 AM
Subject:        Re: [GENERAL] Using ODBC and VBA to pull data from a large object




On Tue, 2013-09-17 at 08:32 -0400, Adam C Falkenberg wrote:
> Good Morning,
>
> I had a question about using ODBC with large objects.  When I query
> the pg_largeobject table and return data to an ADO recordset, I can
> only get the first 255 bytes even though the record contains 2048
> bytes of data (all the bytes after the first 255 show as 0).  When I
> checked the type of the record, it was a VarBinary.  Is there a way to
> have all of the data returned to the recordset?  Thanks for any help.
>
> Adam


Microsofts sample
http://support.microsoft.com/kb/258038


Re: Using ODBC and VBA to pull data from a large object

От
Adam C Falkenberg
Дата:
Sorry about that.  Here's the driver information and some code.  Thanks.

Driver Name: PostgreSQL ANSI
Version: 9.02.01.00

constr = "Driver={PostgreSQL ANSI}; Server=servername; Port=5432; Database=databasename; Uid=username; Pwd=password;"
With conn
    .ConnectionString = (constr)
    .Open
End With

SQL = "SELECT data FROM pg_largeobject WHERE loid = " & id & " ORDER BY pageno"
rs.Open SQL, conn

stream.Type = adTypeBinary
stream.Open
       
' Loop through the recordset and write the binary data to the stream
While Not rs.EOF
    stream.Write rs.Fields("data").Value
    rs.MoveNext
Wend

Adam




From:        Andrew Satori <dru@druware.com>
To:        Adam C Falkenberg <ACFalkenberg@uss.com>,
Date:        09/17/2013 12:02 PM
Subject:        Re: [GENERAL] Using ODBC and VBA to pull data from a large object




You don't say with which driver.  

ODBC can be a bit twitchy with data types, and I have seen several drivers fail when they attempt to read the .Value, some of the driver don't pass through the adTypeBinarry and allocate a MAX_LENGTH string of 255 for the read buffer. I haven't tested the current driver from pg.org, but when I did a few months ago, it correctly handled the .Type field and allocated the length appropriately.

Some version information and source would make this far easier to resolve.

On Sep 17, 2013, at 11:51 AM, Adam C Falkenberg <ACFalkenberg@uss.com> wrote:

> Thanks for the response.  The example you sent is what I tried to follow when I originally worked on this.  It works great for the first 255 bytes, but after that it returns 0's.  Is there any way to get all of the data in a large object returned to a recordset (not just the first 255 bytes)?  Thanks again.
>
> Adam
>
>
>
> From:        Bret Stern <bret_stern@machinemanagement.com>
> To:        Adam C Falkenberg <ACFalkenberg@uss.com>,
> Cc:        pgsql-general@postgresql.org
> Date:        09/17/2013 10:06 AM
> Subject:        Re: [GENERAL] Using ODBC and VBA to pull data from a large object
>
>
>
> On Tue, 2013-09-17 at 08:32 -0400, Adam C Falkenberg wrote:
> > Good Morning,
> >
> > I had a question about using ODBC with large objects.  When I query
> > the pg_largeobject table and return data to an ADO recordset, I can
> > only get the first 255 bytes even though the record contains 2048
> > bytes of data (all the bytes after the first 255 show as 0).  When I
> > checked the type of the record, it was a VarBinary.  Is there a way to
> > have all of the data returned to the recordset?  Thanks for any help.
> >
> > Adam
>
>
> Microsofts sample
>
http://support.microsoft.com/kb/258038
>
>



Re: Using ODBC and VBA to pull data from a large object

От
Vincent Veyron
Дата:
Le mardi 17 septembre 2013 à 12:25 -0400, Adam C Falkenberg a écrit :
> Sorry about that.  Here's the driver information and some code.


> Driver Name: PostgreSQL ANSI
> Version: 9.02.01.00
>
> constr = "Driver={PostgreSQL ANSI}; Server=servername; Port=5432;
> Database=databasename; Uid=username; Pwd=password;"
> With conn
>     .ConnectionString = (constr)
>     .Open
> End With
>
> SQL = "SELECT data FROM pg_largeobject WHERE loid = " & id & " ORDER
> BY pageno"
> rs.Open SQL, conn
>
> stream.Type = adTypeBinary
> stream.Open
>
> ' Loop through the recordset and write the binary data to the stream
> While Not rs.EOF
>     stream.Write rs.Fields("data").Value
>     rs.MoveNext
> Wend


You don't say where you use that recordset (Excel, Access?)

A google search will return several discussions about this problem; here
is an example :


http://social.msdn.microsoft.com/Forums/en-US/32b64a3f-3e7a-4e02-a7ef-824cacfea57a/256-char-limit-on-ado-recordset-field



--
Salutations, Vincent Veyron
http://gdlc.fr/logiciels
Applications de gestion des contentieux juridiques et des dossiers de sinistres assurance



Re: Using ODBC and VBA to pull data from a large object

От
Adam C Falkenberg
Дата:
I'm using Excel.  I needed to set the MAXVARCHARSIZE parameter in the connection string to take care of my issue (MAXVARCHARSIZE=2048 for me).  That allowed the defined size of the field to equal the actual size.  Thanks everyone for your help!

Adam




From:        Vincent Veyron <vv.lists@wanadoo.fr>
To:        Adam C Falkenberg <ACFalkenberg@uss.com>,
Cc:        pgsql-general@postgresql.org
Date:        09/19/2013 04:59 AM
Subject:        Re: [GENERAL] Using ODBC and VBA to pull data from a large object
Sent by:        pgsql-general-owner@postgresql.org




Le mardi 17 septembre 2013 à 12:25 -0400, Adam C Falkenberg a écrit :
> Sorry about that.  Here's the driver information and some code.


> Driver Name: PostgreSQL ANSI
> Version: 9.02.01.00
>
> constr = "Driver={PostgreSQL ANSI}; Server=servername; Port=5432;
> Database=databasename; Uid=username; Pwd=password;"
> With conn
>     .ConnectionString = (constr)
>     .Open
> End With
>
> SQL = "SELECT data FROM pg_largeobject WHERE loid = " & id & " ORDER
> BY pageno"
> rs.Open SQL, conn
>
> stream.Type = adTypeBinary
> stream.Open
>        
> ' Loop through the recordset and write the binary data to the stream
> While Not rs.EOF
>     stream.Write rs.Fields("data").Value
>     rs.MoveNext
> Wend


You don't say where you use that recordset (Excel, Access?)

A google search will return several discussions about this problem; here
is an example :

http://social.msdn.microsoft.com/Forums/en-US/32b64a3f-3e7a-4e02-a7ef-824cacfea57a/256-char-limit-on-ado-recordset-field



--
Salutations, Vincent Veyron
http://gdlc.fr/logiciels
Applications de gestion des contentieux juridiques et des dossiers de sinistres assurance



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