Check if a file exists? - sql

Question

trying to check whether the file I want to read exists or not.

Answer 1

Here are another approaches:
Using BFILE and fileexists function of dbms_lob package:
create or replace function FileExists(
p_DirName in varchar2, -- schema object name
p_FileName in varchar2
) return number
is
l_file_loc bfile;
begin
l_file_loc := bfilename(upper(p_DirName), p_FileName);
return dbms_lob.fileexists(l_file_loc); -- 1 exists; 0 - not exists
end;
Using fgetattr function of utl_file package:
create or replace function FileExists(
p_DirName in varchar2, -- schema object name
p_FileName in varchar2
) return number
is
l_fexists boolean;
l_flen number;
l_bsize number;
l_res number(1);
begin
l_res := 0;
utl_file.fgetattr(upper(p_DirName), p_FileName, l_fexists, l_flen, l_bsize);
if l_fexists
then
l_res := 1;
end if;
return l_res;
end;

Answer 2

Use UTL_FILE.FGETATTR function.
This function is designed specifically for this purpose.
Syntax:
UTL_FILE.FGETATTR(
location IN VARCHAR2,
filename IN VARCHAR2,
fexists OUT BOOLEAN,
file_length OUT NUMBER,
block_size OUT BINARY_INTEGER);
Example:
DECLARE
fexists BOOLEAN;
file_length NUMBER;
block_size BINARY_INTEGER;
BEGIN
UTL_FILE.FGETATTR('MY_ORA_DIRECTORY', 'my_file_name.csv', fexists, file_length, block_size);
IF fexists THEN
-- Do something
-- ...
END IF;
END IF;
Oracle documentation:
https://docs.oracle.com/database/121/ARPLS/u_file.htm#ARPLS70915
One more useful link:
https://www.foxinfotech.in/2018/09/how-to-check-if-file-exists-in-pl-sql.html

Answer 3

Creating a function that checks if a file exists is fairly easy by just trying to open it and catching any exceptions (this example function taken from AskTom)
CREATE OR REPLACE FUNCTION file_exists(p_fname IN VARCHAR2) RETURN BOOLEAN
AS
l_file UTL_FILE.FILE_TYPE;
BEGIN
l_file := UTL_FILE.FOPEN(SUBSTR( p_fname, 1, instr(p_fname,'/',-1) ),
SUBSTR( p_fname, instr( p_fname, '/', -1)+1 ), 'r' );
UTL_FILE.FCLOSE( l_file );
RETURN TRUE;
EXCEPTION
WHEN UTL_FILE.INVALID_PATH THEN RETURN FALSE;
WHEN UTL_FILE.INVALID_OPERATION THEN RETURN FALSE;
END;
/
Then you can just use;
IF ( file_exists( 'MED_LIST_19_OCT_12.csv' ) )
...