Use any of the following approaches
to manage XML tables spaces by using LOCK TABLE statements:
Use LOCK TABLE statements to control the number of locks
acquired on the auxiliary table. Locking the auxiliary
table eliminates the need for lower-level XML locks.
Issue the following statement to prevent other applications
from modifying the data.
LOCK TABLE IN SHARE MODE
Issue the following statement to prevent other applications
from reading the data.
LOCK TABLE IN EXCLUSIVE MODE
This statement also prevents uncommitted readers from accessing
the data in the XML table space. However, it
does not prevent readers from accessing versioned XML documents.