How can I open different binary files from BLOB column ?

Question

If we store some type of binary file (XLS, DOC, PDF, EML and so on, not only pictures) in BLOB column how can I show the different contents? We use designer and forms 9i with PL/SQL.
How can I copy the files from BLOB to file in a directory or how can I pass BLOB's content to the proper application directly to open it?

Answer 1

The mime type is just a string as explained above (e.g. application/pdf...). There are lot of samples here and on metalink.
E.g. add a column mime_type varchar(30) to your blob table. Create a procedure similar to the following:
PROCEDURE getblob
(P_FILE IN VARCHAR2
IS
vblob blob;
vmime_type myblobs.mime_type%type;
length number;
begin
     select document, mime_type into vblob,vmime_type from myblobs where docname = p_file;
     length := dbms_lob.getlength(vblob);
     if length = 0 or vblob is null then
     htp.p('Document not available yet.');
     else
     owa_util.mime_header(vmime_type);
     htp.p('Content-Length: ' || dbms_lob.getlength(vblob));
     owa_util.http_header_close;
     wpg_docload.download_file(vblob);                
     end if;
exception
     when others then
     htp.p(sqlerrm);
END;
Create a DAD on your application server (refer to documentation on how to create a DAD).
Display the blob from forms (e.g. on a when-button-pressed trigger):
web.show_document('http://myserver:port/DAD/getblob?p_file=myfilename','_blank');
For storing blobs in a directory on your db server take a look at the dbms_lob package.
For storing blobs in a directory on your app server take a look at WebUtil available on OTN.
HTH
Gerald Krieger