Differences of 9i & 10g

The major diffferences are-

1.In 9i merge , insert all, case is introduced .
2.In 9i newdatatype called timestamp
3.In 9i you can moniter index using alter index monitering usage
or
u can check user_objects table from system user.
4.In 9i new performance monitering tools called STATPACK .
5.In 9i You can dynamically change init ora parameter using alter system scope=/path/ of your spfile/pfile
6.In 9i new concept for undo transaction called UNDO tablespace
7.In 9i by default TEMP tablespace is considering while creating new oracle users (if we create default temporary tablespace is created it automatically allocated)
8.In 9i new partition called LIST
9.In 9i tablespace next extent can be managed automatically (extent managment local)
10. In 8i tablespace extent management dictionary by default
11.The biggest difference between Oracle8i and Oracle9i is that Oracle9i lets You resize the SGA memory areas dynamically i.e., the Database Buffer Cache DB_CACHE_SIZE or the SHARED_POOL_SIZE, etc., can be resized when the database is up and running. The same is not possible with Oracle8i. You can get more information from OTN
12. You can drop a column in oracle 9i using alter table command where as this is not available in oracle 8i

1) u have automatic undo management.
2)u have automatic segment space management
3)u got these locally managed tablespaces which is better than the dictionary managed tabespaces as u can avoid fragmentation with locally managed tablespaces.
4)u have a new dbms_metadata package to extract object definitions from database.
5)multi table insert is possible with 9i
6)importanly u have this spfile in 9i.
7) also u have dynamic memory mangement facility with 9i.
8) u have tuning advisories with 9i.
9) u have multi block size parameter with 9i and many more features like these..
10. Reduce segment header contention and wasted space within blocks by switching from using FreeLists to Automatic Segment Free Space Management.
11. Replace you existing rollback segments with self-tuning undo segments.
12. Oracle9i Data Guard is the new name for Oracle8i Standby Database incorporating a large number of new features.
..... http://www.oracle-base.com/articles/9i/DataGuard.php ...........

10g features