question about visibilty while updating multiple rows .

Hi,

If an update statement is affecting multiple rows of a table X ,
Does a subselect (selecting from X only)  inside EXISTS part of outer query 
able to see the changes when rows are being updated one by one by outer query?


for example consider following set of data rows:

+------------+-----------------------+------+----------+----------------------------------+
| profile_id |        co_name        | size | deletion |               md5                |
+------------+-----------------------+------+----------+----------------------------------+
|     212161 | ATITH FIBRE PVT. LTD. | FL   | t        | edc462794427724b7d132e3b1387d69f |
|     212159 | ATITH FIBRE PVT. LTD. | 1HS  | f        | edc462794427724b7d132e3b1387d69f |
|     216225 | ATITH FIBRE PVT. LTD. | 1HS  | f        | edc462794427724b7d132e3b1387d69f |
|     216226 | ATITH FIBRE PVT. LTD. | 1HS  | f        | edc462794427724b7d132e3b1387d69f |
+------------+-----------------------+------+----------+----------------------------------+

begin work;

UPDATE eyp_profiles_table SET
       deletion=true 
WHERE 
co_name='ATITH FIBRE PVT. LTD.' AND        deletion is false and EXISTS (select * from eyp_profiles_table a where
a.md5=eyp_profiles_table.md5and      a.deletion is false and a.profile_id <> eyp_profiles_table.profile_id) ;
 


my original problem is to update in such a way that i get below finally (observer the deletion column)
+------------+-----------------------+------+----------+----------------------------------+
| profile_id |        co_name        | size | deletion |               md5                |
+------------+-----------------------+------+----------+----------------------------------+
|     212161 | ATITH FIBRE PVT. LTD. | FL   | t        | edc462794427724b7d132e3b1387d69f |
|     212159 | ATITH FIBRE PVT. LTD. | 1HS  | t        | edc462794427724b7d132e3b1387d69f |
|     216225 | ATITH FIBRE PVT. LTD. | 1HS  | t        | edc462794427724b7d132e3b1387d69f |
|     216226 | ATITH FIBRE PVT. LTD. | 1HS  | f        | edc462794427724b7d132e3b1387d69f |
+------------+-----------------------+------+----------+----------------------------------+
so that only one entry per md5 record exists.



Regds
mallah.






-- 
Rajesh Kumar Mallah,
Project Manager (Development)
Infocom Network Limited, New Delhi
phone: +91(11)6152172 (221) (L) ,9811255597 (M)

Visit http://www.trade-india.com ,
India's Leading B2B eMarketplace.