From the report page I see the <download> tag for that column and I can download the PDF again without problem, but if I try to open again the DML form for that record and I try to change the value of a text column, when I save I get the message "ORA-01400: cannot insert NULL into ..." with reference to the BLOB column.
This comes up from your DML trying to do an insert not an update - Check your DML operation for update of the blob column in the file browser.
but where should I check for the update process for my BLOB column?
Checking the BLOB field parameters I see:
Display As: File Browse...
Value Required: Yes
Storage Type: BLOB columns specified in Item Source attribute
Source Used: Always, replacing any existing value in session state
Source Type: Database Column
and the button for SAVE has:
Action When Button Clicked
Database Action: SQL UPDATE action
I usually don't tune anything after creating the DML page
I've just read the link you've linked to me.
I read this "When the form is called for INSERT, the file selected by the user is loaded into the BLOB column. When the form is called for update, a download link is displayed to the right of the Browse button. Users can use this link to download the file"
The problem is that when I open the DML form on a record already saved (so for update), how can I allow to users to change the content of a field and then save the whole record without having to to download the file? I'm simply updating the record and the content of the BLOB column has noy changed, do you mean?
thanks for your advice of checking the page 6 of the products page in the Sample Database Application.
The difference is that in my SETTINGS of the BLOB item I had Value Required = Yes and so each time the form "pretends" a new value, I suppose. Now, like the example, I have set it to No and everything works.
I haven't understood why only the BLOB item must have No but I don't care: it works and that's all ...