Online material for tablespace and backup

Question

Hi All,
As i am a beginner, can anyone please suggest me any online link for better understanding about tablespace and backup for a beginner.
Thanks in advance
Arun

Answer 1

Hi, follow down a resume did for me in my blog:
Creating Tablespaces Permanent, Temporary and UNDO in ORACLE
Tablespace Datafiles is a set that contains the physical structure of the data storage system Operacional.Sendo thus tablespace is an allocation of space used to store objects of a given user. To create a tablespace in a database, the user will have to have the grant (permission) of Tablespace and Create to create the SYSAUX tablespace (beside SYSTEM, are the most important database), should have the grant of SYSDBA. A tablespace is a logical unit of database and that is part of the following structure:
Database> Tablespace (logical drive)> Datafile (physical file)> Segments (logical drive Example: Tables)> Extents (set of blocks, logical drives) >> Blocks Bank Data (logical unit, a smaller structure database)> Blocks Operating System.
In this article we will be focused on the following types of tablespaces : The permanent tablespaces, the tablespace temporary tablespace and Undo. However, it also will be elucidated creating tablespace with multiple datafiles at once.
- Permanent Tablespaces: Contains a user objects in a database. These objects are stored in physical structures called Datafiles.
SQL> create tablespace TBSEXEBRUNORS
logging
datafile '/ dbbruno/datafiles/datafile1.dbf'
size 64m
autoextend on
next 64m maxsize 2048m
Local extent management uniform size 1m; 2 3 4 5 6 7
Tablespace created.
Creating a Tablespace with multiple Datafiles at once:
SQL> create tablespace TBSMISCBRUNORS
datafile '/ dbbruno/datafiles/datafile2.dbf' size 4M
'/ Dbbruno/datafiles/datafile3.dbf' size 4M
'/ Dbbruno/datafiles/datafile4.dbf' size 4M
logging
extent management site; 2 3 4 5 6
Tablespace created.
It follows a consultation in view DBA_TABLESPACES:
SQL> SET PAGESIZE 180
SQL> SET linesize 180
SQL> SELECT * FROM WHERE DBA_TABLESPACES tablespace_name = 'TBSEXEMPLO' order by 1,2;
Tablespace_name BLOCK_SIZE INITIAL_EXTENT NEXT_EXTENT MIN_EXTENTS MAX_EXTENTS MAX_SIZE PCT_INCREASE MIN_EXTLEN STATUS CONTENTS LOGGING FOR EXTENT_MAN
ALLOCATIO PLU segments DEF_TAB_ RETENTION BIG PREDICA ENC COMPRESS_FOR
TBSEXEMPLO 8192 65536 1 2147483645 2147483645 65536 ONLINE PERMANENT LOGGING NO LOCAL
NO SYSTEM AUTO DISABLED NOT APPLY IN THE HOST
- Clause for managing EXTENTS
The autoallocate clause specifies that the tablespace is managed by ORACLE , and that users can not specify sizes. Moreover, this clause is not allowed to UNDO tablespaces or Temporary. However, the clause UNIFORM specifies that the tablespace is managed by a user (you can specify sizes) via byte sizes, the default 1M (megabyte) to use this clause. Already the LOCAL clause specifies that the tablespace is locally managed and some part of the tablespace is reserved for Bitmap, which is the DEFAULT option for the type of permanent tablespace. But the DICTIONARY clause specifies that you want the tablespace is managed using the data dictionary.
- Management of SEGMENTS clause
The AUTO clause specifies that you want the ORACLE control the free space of segments in the tablespace using BITMAPS. When making use of this option, ORACLE ignores any storage specification later this tablespace. ORACLE strongly recommends using this option. However, this option should only be used in permanent and never tablespaces in a tablespace SYSTEM. However, the clause MANUAL option is not recommended by Oracle, specifies that you want the ORACLE control the free space of segments in the tablespace using freelists (PCTUSED, FREELIST, FREELIST GROUPS).
- Temporary Tablespaces: Contains temporary data for a given session for a given period of time. Furthermore, this type of tablespace tempfiles and have no, Datafiles. This tablespace is used when a user, to which was assigned temporary tablespace, begins operations. Thus, the tablespace temporary stores temporary data used in transactions of users.
SQL> create temporary tablespace TEMPEXEBRUNORS
tempfile '/ dbbruno/datafiles/tempfile1.dbf'
size 128m
autoextend on
next 32m maxsize 2048m
extent management site; 2 3 4 5 6
Tablespace created.
- UNDO Tablespaces or Tablespaces Undo: Tablespace used for operations redone, so that objects can not be created in this tablespace. When this tablespace is created, the ORACLE tablespace SYSTEM takes for you to make such operations. However, the default is to always create an UNDO tablespace when creating the database, so that it is in the mode of automatic undo management.
SQL> create undo tablespace TBSUNDOBRUNORS
datafile '/ dbbruno/datafiles/tbs_datafileundobrunors_1.dbf "
size 200M; 2 3
Tablespace created.
It follows a consultation in view DBA_TABLESPACES:
SQL> SET PAGESIZE 180
SET linesize 180
SELECT tablespace_name, STATUS, RETENTION, SEGMENT_SPACE_MANAGEMENT, EXTENT_MANAGEMENT, INITIAL_EXTENT DBA_TABLESPACES FROM WHERE tablespace_name = 'TBSUNDOBRUNORS' order by 1,2; SQL> SQL>
STATUS tablespace_name RETENTION segments EXTENT_MAN INITIAL_EXTENT
TBSUNDOBRUNORS NOGUARANTEE MANUAL ONLINE LOCAL 65,536
- Clause for retaining segments
The RETENTION GUARANTEE clause specifies that the data store should ORACLE undo expired, even though current operations return fails due to lack of space. This option can be useful in operations FLASHBACK (which is a "flashback" to obtain, for example, the value from a table that was deleted and it is necessary to know the value of that in a certain period). However, the provision RETENTION NOGUARANTEE (as above) specifies that the ORACLE data undo may replace expired undo by new data being processed due to the operations in the current environment, this being the provision pattern.
I hope I helped, hugs!!
References:
http://brunors.com/?p=208