How to write a view

Question

thanks
Edited by: 786304 on May 25, 2011 12:18 PM

Answer 1

Something perhaps along these lines:
Set Serveroutput On
--Create Or Replace Procedure Proc1 As
DECLARE
   ftp_script                     CONSTANT VARCHAR2(60) := 'alter_cre_rules.sql';
   ftp_connect_failure            EXCEPTION;
   ftp_ip_not_found               EXCEPTION;
   ftp_authorization_error        EXCEPTION;
   ftp_file_not_found               EXCEPTION;
   Ftp_Sql                         Varchar2(32767);
   type t_files is table of varchar2(4000) index by pls_integer;
   v_files t_files;
   PRAGMA EXCEPTION_INIT(ftp_connect_failure,-20504);
   PRAGMA EXCEPTION_INIT(ftp_ip_not_found,-6512);
   PRAGMA EXCEPTION_INIT(ftp_authorization_error,-1451);
   PRAGMA EXCEPTION_INIT(ftp_file_not_found,-2260);
   --PRAGMA EXCEPTION_INIT(lex_already_uk,-2261); 
BEGIN
   dbms_output.put_line('Executing script '||ftp_script);
   ftp_sql := 'CREATE OR REPLACE VIEW V_LIST_OF_FILES_FTP AS' ||
' SELECT COLUMN_VALUE AS EACH_FILE' ||
    ' FROM TABLE(
        XUTL_FTP.LIST(' ||
                       '(SELECT XUTL_FTP.START_SESSION(''192.168.50.7'',''vigo'',''vigo'') FROM DUAL WHERE ROWNUM=1), ''/vigo/a.txt''
   Execute Immediate Ftp_Sql;
   execute immediate 'select * from v_list_of_files_ftp' bulk collect into v_files;
   dbms_output.put_line('Executed: '||SUBSTR(ftp_sql,1,120));
EXCEPTION
  WHEN ftp_connection_failure THEN
    -- Do whatever needs doing if the connection_fails
    NULL;
  WHEN ftp_ip_not_found THEN
    -- Do whatever needs doing if the IP address is not found
    NULL;
  WHEN ftp_authorization_error THEN
    -- Do whatever needs doing if the authorization is wrong
    NULL;
END;
/ As you can see, the problem with dynamically creating a view at run-time is that, to use it, you have to dynamically write your SQL queries too. Proper design would create the view once on the database as part of the database design and then any code developed against the database can compile against it and just use it without having to work dynamically.
Edited by: BluShadow on 14-Mar-2011 12:11
updated based on the reply above.