When we tried to change tablespace storage paramters in a DBCA created database, we may get the following error information because the storage settings for locally managed tablespaces cannot be altered.

ORA-25143: default storage clause is not compatible with allocation policy.

Or, if you want to create a tablespace dictionary managed, you might get this error information:

ORA-12913: Cannot create dictionary managed tablespace

In Unix, type “oerr ora 12913″, you’ll get:

*Cause: Attemp to create dictionary managed tablespace in database which has system tablespace as locally manged

*Action: Create a locally managed tablespace.

Using the following SQL scripts, you will find the status of SYSTEM tablespace.

select tablespace_name, extent_management
from dba_tablespaces
where tablespace_name = ‘SYSTEM’;

TABLESPACE_NAME EXTENT_MAN
—————- ———–
SYSTEM LOCAL

Every Oracle database contains a tablespace named SYSTEM, which Oracle creates automatically when the database is created. The SYSTEM tablespace is always online when the database is open. DBCA creates by default a database with locally managed system tablespace.

To take advantage of the benefits of locally managed tablespaces, you can create a locally managed SYSTEM tablespace, or you can migrate an existing dictionary managed SYSTEM tablespace to a locally managed format.

In a database with a locally managed SYSTEM tablespace, dictionary managed tablespaces cannot be created. It is possible to plug in a dictionary managed tablespace using the transportable feature, but it cannot be made writable.

Once a tablespace is locally managed, it cannot be reverted back to being dictionary managed.

You can create a database with a dictionary managed system tablespace. A simple SQL script can be created and then executed via SQL*Plus which will create your database with all the options you might want. A simple example:

create database yourdb controlfile reuse
maxdatafiles 1064
character set “AL32UTF8″
national character set “UTF8″
datafile
‘d:\yourfilesystem\yourdb_system_01.dbf’ size 250M
extent management dictionary
undo tablespace yourdb_undo
datafile ‘d:\anotherfilesystem\yourdb_undo_01.dbf’ size 400M
logfile
group 1 (………… etc… etc.

This is a very simplistic example with limited options included. You can check the “create database” command options in any Oracle reference with the appropriate version of database you are using. The GUI tools such as DBCA don’t always provide the easiest nor complete options available for managing your Oracle databases.

Reference: Oracle 9i How to Create Dictionary Managed Tablespace