Two cursors accessing the same records

[Ruslan Zasukhin]

On 12/16/05 7:31 PM, "Dave Addey" <listmail1 at dsl.pipex.com> wrote:

Hi Dave,

> Hi there,
> 
> Is it safe for me to have one cursor open on a table, accessing various
> records for read only, and then to open another cursor for one record in the
> table, to read and update its values?

Second cursor will be able do this only for a record(s) not selected by
first cursor. 

You cannot get WRITE lock on a record which have at least one reader.

> Will the first cursor¹s values get updated when I UpdateRecord in the second
> cursor?  

> What locks, if any, should I put in place?

Well, you can get behavior which you describe if you will do

    curs1 = db.Select( query, kServerSide, kNoLocks )

    curs2 = db.Select( query, kServerSide, kReadWrite )

So first cursor do not lock records at all.

YES first cursor will see changes made by second cursor.
This is like transaction mode: DIRTY READ.


-- 
Best regards,

Ruslan Zasukhin
VP Engineering and New Technology
Paradigma Software, Inc

Valentina - Joining Worlds of Information
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