• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 2523
  • Last Modified:

How to export a blob field to Windows folder?

Hello ,

My postgres table has a blob field that stores MS-Word files. I need to loop the table and export each blob field as a Word document to a Windows folder.

I'm using pgAdmin, and trying to do this:

SELECT lo_export(bl_mydocument, 'C:\x\MyDocument.doc')
  FROM MyTable
  where bl_field='514-2009';

Got this error:

ERROR:  function lo_export(bytea, "unknown") does not exist
HINT:  No function matches the given name and argument types. You may need to add explicit type casts.

********** Error **********

ERROR: function lo_export(bytea, "unknown") does not exist
SQL state: 42883
Hint: No function matches the given name and argument types. You may need to add explicit type casts.

My Postgres database has this software version:
- PostgreSQL 7.4.2
- O/S: Conectiva Linux 10

Client:
pgAdmin Version 1.10.5, in Windows XP
0
miyahira
Asked:
miyahira
  • 3
  • 2
1 Solution
 
miyahiraAuthor Commented:
Also, I'm trying to run that function using OID parameter:

SELECT lo_export(1202474, 'C:\x\MyDocument.doc')
  FROM MyTable
  where bl_field='514-2009';

but got error:


ERROR:  large object 1202474 does not exist

********** Error **********

ERROR: large object 1202474 does not exist
SQL state: 42704
0
 
earth man2Commented:
SELECT bl_mydocument FROM MyTable where bl_field='514-2009';
SELECT bl_mydocument::oid FROM MyTable where bl_field='514-2009';
SELECT lo_export(bl_mydocument::oid, 'C:\x\MyDocument.doc') FROM MyTable where bl_field='514-2009';
SELECT lo_export(1202474:oid, 'C:\x\MyDocument.doc') ;

MyTable.bl_mydocument has probably been defined as bytea type where it is probably better off being an oid type.
0
 
miyahiraAuthor Commented:
Thanks for the response. You are right, field bl_mydocument is bytea type, not oid type. Actually, I realized that lo_export function does not work for bytea types. At the end, I had to make a program with .net to extract all blobs.

I think that postgres has no function to export data from bytea types. Am I right?
0
 
earth man2Commented:
The author took my hints and arrived at a solution, then asks a rhetorical question....
0
 
miyahiraAuthor Commented:
Didn't get response after my last comment.
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

Featured Post

Cloud Class® Course: Microsoft Azure 2017

Azure has a changed a lot since it was originally introduce by adding new services and features. Do you know everything you need to about Azure? This course will teach you about the Azure App Service, monitoring and application insights, DevOps, and Team Services.

  • 3
  • 2
Tackle projects and never again get stuck behind a technical roadblock.
Join Now