What is the difference between the views nls_database_parameters and nls_instance_parameters?

The NLS_DATABASE_PARAMETERS view will display what the NLS settings were when the database was created. These are fixed at the database level and cannot be changed.

The NLS_INSTANCE_PARAMETERS view reflects parameters set for your instance in the init.ora file or the server parameter file (spfile).


Source: James Koopman in Databasejournal.com

This matches my settings for a random database:

SQL> show parameter nls_
 
NAME                                  TYPE        VALUE
 ------------------------------------ ----------- ------------------------------
 nls_comp                             string      BINARY
 nls_language                         string      AMERICAN
 nls_length_semantics                 string      BYTE
 nls_nchar_conv_excp                  string      FALSE
 nls_territory                        string      AMERICA
 
SQL> SELECT * FROM NLS_INSTANCE_PARAMETERS WHERE value IS NOT NULL;
 
PARAMETER                       VALUE
 ------------------------------ ----------------------------------------
 NLS_LANGUAGE                   AMERICAN
 NLS_TERRITORY                  AMERICA
 NLS_COMP                       BINARY
 NLS_LENGTH_SEMANTICS           BYTE
 NLS_NCHAR_CONV_EXCP            FALSE
 
5 rows selected.

What are literals?

The terms "literal" and "constant" are synonymous and refer to a fixed data value.

There are:

•Text Literals
Examples: 'JACK', 'BLUE ISLAND', '101'.

•Numeric Literals
Examples: 5001, +256

•Datetime Literals
Example: DATE '1998-12-25'.

Note that the ANSI (American National Standards Institute) date literal contains no time portion.

•Interval Literals
Examples:
INTERVAL '123-2' YEAR(3) TO MONTH
INTERVAL '4 5:12:10.222' DAY TO SECOND(3)


Source: Oracle Documentation

How to instruct OUI to ignore prerequisites

./runinstaller -ignoreSysPrereqs

Using the procedure SEARCHFILES in DBMS_BACKUP_RESTORE

I found the following great article about how to list files in directory from within sqlplus here, written by David Marco. As pointed out by several oracle bloggers, there is very little documentation around for this package.

It just so happened that a user was in need of such functionality, and his code could be used straight-off.

However, my customer had already ammended a very useful functionality, by adding support for sending the directory name in as a parameter.

The code as it looks now:

CREATE OR REPLACE FUNCTION LIST_FILES( p_directory IN VARCHAR2, p_file_pattern IN VARCHAR2 default null)
RETURN file_array pipelined AS

l_path VARCHAR2(1024);
l_dummy VARCHAR2(1024);

BEGIN

   SELECT directory_path
   INTO l_path
   FROM all_directories
   WHERE directory_name = p_directory;

   sys.DBMS_BACKUP_RESTORE.SEARCHFILES(l_path, l_dummy);

   FOR file_list IN (SELECT FNAME_KRBMSFT AS file_name
                     FROM X$KRBMSFT
                     WHERE FNAME_KRBMSFT LIKE '%'|| NVL(p_file_pattern, FNAME_KRBMSFT)||'%' ) LOOP
      PIPE ROW(file_list.file_name);
   END LOOP;

END;
/

The call will thus be:

SELECT * FROM TABLE(LIST_FILES('MY_DIR','%*.dmp%'));

What are nodeapps in an Oracle RAC environment?

Nodeapps are a standard set of Oracle application services that are automatically launched for RAC (Real Application Cluster). The following service are lunched by nodeapps:

•Virtual IP (VIP)
•Oracle Net Listener
•Global Services Daemon (GSD)
•Oracle Notification Service (ONS)

Nodeapp services that run on each node can be relocated to other nodes through the virtual IP.

How to use the dbms_metadata package to generate DDL for a user

-- Arg #1 schema name
-- Arg #2 DB Directory
whenever sqlerror exit 1
whenever oserror  exit 2
set long 100000 verify off feedback off
accept user_name prompt 'User name: '
accept directory_name prompt 'Directory name to write to: '
declare
begin
DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM,'SQLTERMINATOR',TRUE);
declare
no_grant      EXCEPTION;
PRAGMA EXCEPTION_INIT (no_grant, -31608);
CURSOR get_username
IS
SELECT username
FROM all_users
WHERE username = UPPER('&user_name');

file_handle   UTL_FILE.file_type;
stmt          CLOB;
BEGIN
file_handle := UTL_FILE.fopen(UPPER('&directory_name'), 'cr_user_&user_name..sql', 'w', 32767);

FOR l_user IN get_username
LOOP

-- USERS
stmt:=DBMS_METADATA.get_ddl('USER', l_user.username)||chr(10);
begin
stmt:=stmt||'---------------------------------------'||chr(10);
stmt:=stmt||'-- SYSTEM_GRANT'||chr(10);
stmt:=stmt||'---------------------------------------'||chr(10);
stmt:=stmt||DBMS_METADATA.get_granted_ddl('SYSTEM_GRANT', l_user.username)||chr(10);
exception
when no_grant then stmt := stmt||'-- no system grants'||chr(10);
end;
begin
stmt:=stmt||'---------------------------------------'||chr(10);
stmt:=stmt||'-- OBJECT_GRANT'||chr(10);
stmt:=stmt||'---------------------------------------'||chr(10);
stmt:=stmt||DBMS_METADATA.get_granted_ddl('OBJECT_GRANT', l_user.username)||chr(10);
exception
when no_grant then stmt := stmt||'-- no object grants'||chr(10);
end;
begin
stmt:=stmt||'---------------------------------------'||chr(10);
stmt:=stmt||'-- ROLE_GRANT'||chr(10);
stmt:=stmt||'---------------------------------------'||chr(10);
stmt := stmt||DBMS_METADATA.GET_GRANTED_DDL('ROLE_GRANT', l_user.username)||chr(10);
exception
when no_grant then stmt := stmt||'-- no role grants'||chr(10);
end;
begin
stmt:=stmt||'---------------------------------------'||chr(10);
stmt:=stmt||'-- TABLESPACE_QUOTA'||chr(10);
stmt:=stmt||'---------------------------------------'||chr(10);
stmt:=stmt||DBMS_METADATA.GET_GRANTED_DDL('TABLESPACE_QUOTA',l_user.username)||chr(10);
exception
when no_grant then stmt := stmt||'-- no tablespace quota'||chr(10);
end;
begin
stmt:=stmt||'---------------------------------------'||chr(10);
stmt:=stmt||'-- DEFAULT_ROLE'||chr(10);
stmt:=stmt||'---------------------------------------'||chr(10);
stmt := stmt||DBMS_METADATA.GET_GRANTED_DDL('DEFAULT_ROLE', l_user.username)||chr(10);
exception
when no_grant then stmt := stmt||'-- no default role'||chr(10);
end;

UTL_FILE.put (file_handle, stmt);

end loop;
UTL_FILE.fclose (file_handle);
END;
DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM,'SQLTERMINATOR',FALSE);
end;

/
exit

How to use the dbms_metadata package to generate DDL for table

accept table_name prompt 'Table name: '
accept owner prompt 'Table owner: '

set long 90000
set longchunksize 300
set pagesize 0
set linesize 300
set trimspool on
set heading off
set verify off
set echo off
set feedback off
spool table_ddl.lst

exec DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM,'SEGMENT_ATTRIBUTES',FALSE);
exec DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM,'STORAGE',TRUE);
exec DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM,'SQLTERMINATOR',TRUE);
select dbms_metadata.get_ddl('TABLE',UPPER('&&table_name'),UPPER('&&owner'))
from dba_tables where table_name = UPPER('&&table_name');
exit