Insomnia can be caused by psychiatric conditions such as depression. Psychological struggles can make it hard to sleep, insomnia itself can bring on changes in mood, and shifts in hormones and physiology can lead to both psychiatric issues and insomnia at the same time.
A lock is a variable associated with a data item that describes the status of the item with respect to possible operations that can be applied to it. Generally, there is one lock for each data item in the database.Locks are used as a means of synchronizing the access by concurrent transactions to the database item. Types of Locks. Several types of locks are used in concurrency control.inary Locks. A binary lock can have two states or values: locked and unlocked. A distinct lock is associated with each database item A. If the value of the lock on A is 1, item A cannot be accessed by a database operation that requests the item.
1 In the $lock table, type values include TM for table locks, TX for transaction locks, MR for media recovery locks and ST for disk space locks.  2 Lmode and request are meaningful when their values are compared together. 3  Only one can be equal to zero or one at the same time.eview the v$lock. Oracle table for locking information. Use the select command to view sid, type, lmode and request.. Sid stands for session ID number and identifies the session that owns the lock.