Illustrate different types of Locks in SQL Server.
There are three kinds of locks in SQL Server
i.) Shared locks - These are used for operations which don't allow any update or change of data. For example SELECT.
ii.) Update locks - These are used when SQL Server wants to modify a page. Update page lock is then promoted to an exclusive page lock before actually making changes.
iii.) Exclusive locks - they are used for data modification operations. For example UPDATE, INSERT, or DELETE.