In a multiuser environment, Adaptive Server must prevent simultaneous queries and data modification requests from interfering with each other. This is important because if the data being processed by a query can be changed by another user’s update, the results of the query may be ambiguous.
Adaptive Server automatically sets the appropriate level of locking for each transaction. You can make shared locks more restrictive on a query-by-query basis by including the holdlock keyword in a select statement.
