Num of extents for a table???

[Prettyman]

Which data dictionary view could you query to display the number of extents allocated to the employee table?

A. DBA_EXTENTS
B. DBA_FREE _SPACE
C. USER_TABLES
D. DBA_TABLES
E. DBA_TABLESPACES

I don't think there is a right answer!

[pando]

dba_extents of course

[ehaskins]

Yes, DBA_EXTENTS using the SEGMENT_NAME column for the name of the table, SEGMENT_TYPE for 'TABLE', and possibly OWNER if you knew whose schema it belonged to.

You'll have to do a little math based on the storage setting of the table, but DBA_EXTENTS will give you BYTES and BLOCKS.

[Prettyman]

So we have to know the storage parameters for the table to calculate the num of extents by bytes or blocks??? I don't know if it is a real exam question, only saw it somewhere and wrote it down.

[jmodic]

No, you don't need any information on storage parameters of a table to get the number of its extents from the DBA_EXTENTS view. The most simple query from it will give you the answer:

SELECT COUNT(*) AS number_of_extents
FROM dba_extents
WHERE owner = 'THE_OWNER'
AND segment_name = 'THE_TABLE';

[Prettyman]

Thx a lot, clear now. :-) I'm still a little bit mess for data dictionary view.

[ehaskins]

O.K., somebody smack me if I'm not seeing what JMODIC is attempting to do with the COUNT(*) above. I know it's late...1:20am (and I did drink a couple beers tonight), but COUNT(*) on the dba_extents view to obtain the number of extents allocated to a particular table?? Maybe it will make sense in the morning!

[pando]

he is just showing it how can you obtain number of extents from dba_extents

[ehaskins]

ooops, my bad...much clearer now that it's morning! ;-)