SQL Server- Limit to Concurrent table queries? In SQL Server, or RDBMS systems in general, is there a limit to the number of concurrent queries that can be made against a table?  How is it that N number of users can access the same physical data at the same time?

Update

Actually, more generally, forgetting about limits, how is it that two users can read from a table at the same time. Can someone explain this from a technical perceptive?  If data is stored in a physical space on a disk, how is it that two users / processes can query that same physical data at the same time?
How is it that N number of users can access the same physical data at the same time?


This is done using transactions (honors ACID properties) &amp; concurrency models. SQL server supports Optimistic concurrency as well as Pessimistic concurrency (default concurrency model) which inturn uses different isolation levels (read committed is the default isolation level ) and locking mechanism to allow multiple users access the data at the same time.

Refer to : SQL Server Transaction Locking and Row Versioning Guide