Question around UTL_FILE and writing unicode data to a file.

Question

Database version : 11.2.0.3.0
NLS_CHARACTERSET : AL32UTF8
OS : Red Hat Enterprise Linux Server release 6.3 (Santiago)
I did not work with multiple language characters and manipulating them. So, the basic idea is to write UTF8 data as Unicode file using UTL_FILE. This is fairly an empty database and does not have any rows in at least the tables I am working on. First I inserted a row with English characters in the columns.
I used utl_file.fopen_nchar to open and used utl_file.put_line_nchar to write it to the file on the Linux box. I open the file and I still see English characters (say "02CANMLKR001".
Now, I updated the row with some columns having Chinese characters and ran the same script. It wrote the file. Now when I "vi" the file, I see "02CANè¹æ001" (some Unicode symbols in place of the Chinese characters and the regular English.
When I FTP the file to windows and open it using notepad/notepad++ it still shows the Chinese characters. Using textpad, it shows ? in place of Chinese characters and the file properties say that the file is of type UNIX/UTF-8.
My question : "Is my code working and writing the file in unicode? If not what are the required changes?" -- I know the question is little vague, but any questions/suggestions towards answering my question would really help.
sample code:
{pre}
DECLARE
   l_file_handle   UTL_FILE.file_type;
   l_file_name     VARCHAR2 (50) := 'test.dat';
   l_rec           VARCHAR2 (250);
BEGIN
   l_file_handle := UTL_FILE.fopen_nchar ('OUTPUT_DIR', l_file_name, 'W');
   SELECT col1 || col2 || col3 INTO l_rec FROM table_name;
   UTL_FILE.put_line_nchar (l_file_handle, l_rec);
   UTL_FILE.fclose (l_file_handle);
END;
{/pre}

Answer 1

Regardless of what you think of my reply I'm trying to help you.
I think you need to reread my reply because I can't find ANY relation at all between what I said and what you responded with.
I wish things are the way you mentioned and followed text books.
Nothing in my reply is related to 'text books' or some 'academic' approach to development. Strictly based on real-world experience of 25+ years.
Unfortunately lot of real world projects kick off without complete information.
No disagreement here - but totally irrevelant to anything I said.
Till we get the complete information, it's better to work on the idea rather than wasting project hours. I don't think it can work that way. All we do is to lay a ground preparation, toy around multiple options for the actual coding even when we do not have the exact requirements.
No disagreement here - but totally irrevelant to anything I said.
And I think it's a good practice rather than waiting for complete information and pushing others.
You can't just wait. But you also can't just go ahead on your own. You have to IMMEDIATELY 'push others' as soon as you discover any issues affecting your team's (or your) ability to meet the requirements. As I said above:
Your problems are likely:
1. lack of adequate requirements as to what the vendor really requires in terms of format and content
2. lack of appropriate sample data - either you don't have the skill set to create it yourself or you haven't gotten any from someone else.
3. lack of knowledge of the character sets involved to be able to create/conduct the proper tests
If you discover something missing with the requirements (what character sets need to be used, what file format to use, whether BOMs are required in the file, etc) you simply MUST bring that to your manager's attention as soon as you suspect it might be an issue.
It is your manager's job, not yours, to make sure you have the tools needed to do the job. One of those tools is the proper requirements. If there is ANYTHING wrong, or if you even THINK something is wrong with those requirements it is YOUR responsibility to notify your manager ASAP.
Send them an email, leave a yellow-sticky on their desk but notify them. Nothing in what I just said says, or implies, that you should then just sit back and WAIT until that issue is resolved.
If you know you will need sample data you MUST make sure the project plan includes SOME means to obtain sample data witihin the timeline needed by your project. As I repeated above if you don't have the skill set to create it yourself someone else will need to do it.
I did not work with multiple language characters and manipulating them.
Does your manager know that? If the project requires 'work with multiple language characters and manipulating them' someone on the project needs to have experience doing that. If your manager knows you don't have that experience but wants you to proceed anyway and/or won't provide any other resource that does have that experience that is ok. But that is the manager's responsibility and that needs to be documented. At a minimum you need to advise your manager (I prefer to do it with an email) along the following lines:
Hey - manager person - As you know I have little or no experience to 'work with multiple language characters and manipulating them' and those skills are needed to properly implement and test that the requirements are met. Please let me know if such a resource can be made available.
And I'm serious about that. Sometimes you have to make you manager do their job. That means you ALWAYS need to keep them advised of ANY issue that might affect the project. Once your manager is made aware of an issue it is then THEIR responsibility to deal with it. They may choose to ignore it, pretend they never heard about it or actually deal with it. But you will always be able to show that you notified them about it.
Now, I updated the row with some columns having Chinese characters and ran the same script.
Great - as long as you actually know Chinese that is; and how to work with Chinese characters in the context of a database character set, querying, creating files, etc.
If you don't know Chinese or haven't actually worked with Chinese characters in that context then the project still needs a resource that does know it.
You can't just try to bluff your way through something like character sets and code conversions. You either know what a BOM (byte order mark) is or you don't. You have either learned when BOMs are needed or you haven't.
That said, we are in process of getting the information and sample data that we require.
Good!
Now make sure you have notified your manager of any 'holes' in the requirements and keep them up to date with any other issues that arise.
NONE of the above suggests, or implies, that you should just sit back and wait until that is done. But any advice offered on the forums about specifics of your issue (such as whether you need to even worry about BOMs) is premature until the vendor or the requirements actually document the precise character set and file format needed.