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Message Posted: Mon, 28 Jan 2008 @ 21:55:09 GMT


     
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Subj:   Re: Locking Row for Access Stmt
 
From:   Sapra, Kapil Dev

Hi,

LOCKING <tablename> FOR ACCESS : user can select all data in table during updating/insertion.

[Permits the user to access for READ an object that may be already locked for READ or WRITE An ACCESS lock does not restrict access by another user except when an EXCLUSIVE lock is required. A user requesting access disregards all data consistency issues.]

'LOCKING ROW FOR ACCESS' : This is related to row hash lock. A row hash lock applies to a set of rows that shares the same hash code. It does not necessarily, nor even generally, lock only one row.

Few points related to row has.

* A row hash lock is applied whenever a table is accessed using a unique primary index (UPI).

* For an update that uses a unique secondary index (USI), the appropriate row of the secondary index subtable is also locked.

* It is not necessary to lock the fallback copy of the row, nor any associated row, of a nonunique secondary index (NUSI) subtable.


Best of Luck!!!! Thanks.

Kapil D Sapra



     
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