Lock
Owners 
Definition
Person who holds a lock.
Use
At the start of an SAP transaction, two owners are always created who can request locks.
A lock can have one or two owners. You use the _SCOPE parameter to specify this.
To determine in a program which user is currently holding a lock, use the ENQUEUE_ function module. This function module puts the name of the owner into SY-MSGV1.
Structure
There are dialog owners and update owners.
An owner is identified by his or her owner ID, as described in the section entitled The Lock Table.
A lock can have one or two owners. The ABAP programmer uses the _SCOPE parameter to define this (see below).
Example
The graphic below shows how lock owners function during a dialog transaction.
SAP LUW: Dialog Transaction with Update
At the start of the dialog transaction, the system creates two lock owners: the dialog owner Owner_1 and the update owner Owner_2.
During the
course of the transaction, Owner_1 requests a lock, as does Owner_2 slightly
later. When the update task is called (see also 
Functions of the
Update Task), the lock and Owner_2 are inherited by the update task. An
update work process is started with two owners, in the same way as a dialog
work process, and then has three owners until the update is completed. All of
the locks are released with an implicit DEQUEUE_ALL at the end of the update,
at the latest.
See also: