what are the ypes of locking available in SQL

1)Shared locks are used for operations that does not allow to change or update data, such as a SELECT statement.
(2)Update locks are used when SQL Server intends to modify a page, and later promotes the update page lock to an exclusive page lock before actually making the changes.
(3)Exclusive locks are used for the data modification operations, such as UPDATE, INSERT, or DELETE


SHARED - This lock is applied for read operation where the data is not updated. A good example would be the select statement.

UPDATE – This locked on those resources that can be updated. This lock prevents the common form of dead lock that occurs when multiple sessions are locking the data so that they can update it later.

EXCLUSIVE - Used for data-modification operations, such as INSERT, UPDATE, or DELETE. Ensures that multiple updates cannot be made to the same resource at the same time.

INTENT - Used to establish a lock hierarchy. The different types of intent locks are: intent shared, intent exclusive, and shared with intent exclusive.

SCHEMA - Used when an operation dependent on the schema of a table is executing. The different types of schema locks are: schema modification and schema stability.

BULK UPDATE – This lock is applied when there is a bulk copying of data and the TABLOCK is applied

KEY RANGE - Protects the range of rows read by a query when using the serializable transaction isolation level. Ensures that other transactions cannot insert rows that would qualify for the queries of the serializable transaction if the queries were run again