How to get all XML file names from a directory using EXTERNAL TABLE - oracle

Question

I am trying to get all XML file names present in a directory in order to feed them to a procedure which pulls data out of those files. Could anyone help with how I can get the file name using the EXTERNAL TABLE.
I am having trouble with ACCESS PARAMETERS and LOCATION file. Don't know what exactly would go there.
Thanks
CREATE TABLE S7303786.XML_FILES
(
FILE_NAME VARCHAR2(255 CHAR)
)
ORGANIZATION EXTERNAL
(
TYPE ORACLE_LOADER
DEFAULT DIRECTORY AUTOACCEPT_XMLDIR
ACCESS PARAMETERS
(
RECORDS DELIMITED BY NEWLINE
PREPROCESSOR AUTOACCEPT_XMLDIR: 'list_file.sh'
FIELDS TERMINATED BY WHITESPACE
)
LOCATION ('list_file.sh')
)
REJECT LIMIT UNLIMITED;
list_files.sh just contains the directory where the files are present.
sticky.txt has nothing in it
error I am getting are :
ORA-29913: error in executing ODCIEXTTABLEFETCH callout
ORA-29400: data cartridge error
KUP-04004: error while reading file /home/transfer/stu/nshstrans/sticky.txt

Answer 1

Error you got might have something to do with directory, Oracle object which points to physical directory on database server's disk. It is created by a privileged user - SYS, who then grants read and/or write privileges on it to users who will use it.
If you missed to do anything of above mentioned things, your external table won't work.
So:
SQL> show user
USER is "SYS"
SQL>
SQL> create directory mydir as 'c:\temp';
Directory created.
SQL> grant read, write on directory mydir to scott;
Grant succeeded.
SQL>
Connect to Scott and create external table:
SQL> connect scott/tiger
Connected.
SQL> create table extusers
2 (username varchar2(20),
3 country varchar2(20)
4 )
5 organization external
6 (type oracle_loader
7 default directory mydir --> this is directory I created
8 access parameters
9 (records delimited by newline
10 fields terminated by ';'
11 missing field values are null
12 (username char(20),
13 country char(20)
14 )
15 )
16 location ('mydata.txt') --> name of the file that contains data
17 ) -- located in c:\temp, which is MYDIR
18 reject limit unlimited -- directory
19 /
Table created.
SQL>
Contents of the sample text file:
SQL> $type c:\temp\mydata.txt
Littlefoot;Croatia
Michel;France
Maaher;Netherlands
SQL>
Finally, let's select from the external table:
SQL> select * from extusers;
USERNAME COUNTRY
-------------------- --------------------
Littlefoot Croatia
Michel France
Maaher Netherlands
SQL>
Works OK, doesn't it? Now, try to do what I did.
On a second reading,
it appears that you don't want to read file contents, but directory contents. If that's so - apparently, it is - then see whether this helps.
In order to make it work, privileged user has to grant additional privilege - EXECUTE - to the directory.
SQL> show user
USER is "SYS"
SQL> grant execute on directory mydir to scott;
Grant succeeded.
Next step is to create an operating system executable (on MS Windows I use, it is a .bat script; on Unix, that would be a .sh, I think) which will list the directory. Note the first line - I have to navigate to a directory which is source for Oracle directory object. If you don't do that, it won't work. The .bat file is simple:
SQL> $type c:\temp\directory_contents.bat
cd c:\temp
dir /b *.txt
SQL>
Create external table:
SQL> create table extdir
2 (line varchar2(50))
3 organization external
4 (type oracle_loader
5 default directory mydir
6 access parameters
7 (records delimited by newline
8 preprocessor mydir:'directory_contents.bat'
9 fields terminated by "|" ldrtrim
10 )
11 location ('directory_contents.bat')
12 )
13 reject limit unlimited
14 /
Table created.
SQL> connect scott/tiger
Connected.
Let's see what it returns:
SQL> select * From extdir;
LINE
-----------------------------------------------
c:\Temp>dir /b *.txt
a.txt
dept.txt
emp.txt
emps.txt
externalfile1.txt
lab18.txt
mydata.txt
p.txt
parfile_01.txt
sofile.txt
test.txt
test2.txt
15 rows selected.
SQL>
Well ... yes, those are my .txt files located in c:\temp directory.
As you use *nix, I think that problem you got is related to list_files.sh script. You didn't post its contents (which would probably help - not necessarily help me as I forgot almost everything I knew about *.nix), but - regarding Preprocessing External Tables (written by Michael McLaughlin), you might need to
prepend /usr/bin before the ls, find, and sed programs: /usr/bin/ls ...
See if it helps.