How can i know the table fragments

Question

Hi
How can i know the table is fragmented.
Thank you

Answer 1

If you're in 10g you could try use the Segment Advisor to identify various issues etc with your table. This will also provide recommendations on how to improve things.
(below script shamelessly stolen from the brilliant Oracle Base website)
-- segment_adv_table.sql
-- Use Segment Advisor to analyse a table.
-- Original Version
-- http://www.oracle-base.com/articles/10g/SpaceObjectTransactionManagement10g.php
-- owner is SCOTT
-- table is EMP
-- do a search/replace to change these 2 values and re-run it ;)
DECLARE
l_object_id NUMBER;
BEGIN
-- Create a segment advisor task for the SCOTT.EMP table.
DBMS_ADVISOR.create_task (
advisor_name => 'Segment Advisor',
task_name => 'EMP_SEGMENT_ADVISOR',
task_desc => 'Segment Advisor For EMP');
DBMS_ADVISOR.create_object (
task_name => 'EMP_SEGMENT_ADVISOR',
object_type => 'TABLE',
attr1 => 'SCOTT',
attr2 => 'EMP',
attr3 => NULL,
attr4 => 'null',
attr5 => NULL,
object_id => l_object_id);
DBMS_ADVISOR.set_task_parameter (
task_name => 'EMP_SEGMENT_ADVISOR',
parameter => 'RECOMMEND_ALL',
value => 'TRUE');
DBMS_ADVISOR.execute_task(task_name => 'EMP_SEGMENT_ADVISOR');
END;
-- Display the findings.
SET LINESIZE 250
COLUMN task_name FORMAT A20
COLUMN object_type FORMAT A20
COLUMN schema FORMAT A20
COLUMN object_name FORMAT A30
COLUMN object_name FORMAT A30
COLUMN message FORMAT A40
COLUMN more_info FORMAT A40
SELECT f.task_name,
f.impact,
o.type AS object_type,
o.attr1 AS schema,
o.attr2 AS object_name,
f.message,
f.more_info
FROM dba_advisor_findings f
JOIN dba_advisor_objects o ON f.object_id = o.object_id AND f.task_name = o.task_name
WHERE f.task_name IN ('EMP_SEGMENT_ADVISOR', 'USERS_SEGMENT_ADVISOR')
ORDER BY f.task_name, f.impact DESC;