On 7/6/2011 1:48 AM, Jens wrote:
> You have to store the lock somehow in the database. For example you
> can create a database table called "locked objects" that has columns
> like "id, referenced table name, referenced object id, user id that
> locked the object, date of lock". Then you put a unique constraint on
> "referenced table name, referenced object id" so that a object can not
> be locked twice. 
>
> On server side you can then implement methods like
> Lock.create(CommonEntityInterface object),
> Lock.delete(CommonEntityInterface object) and maybe
> Lock.isLocked(CommonEntityInterface object) where
> CommonEntityInterface is just an interface (or an abstract entity base
> class) implemented by all your entities so you can call getId() on
> them. The table name can be accessed via the @Table annotation
> (reflection) or has to be generated if you use JPA default table names.
>
> -- J.
> --
Why not use a set transaction statement that locks the desired row?
Isn't that why we use a DBMS?

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