Sybase IQ allows multiple users to query a database at the same time, while another user inserts or deletes data, or backs up the database. Changes to the structure of the database, such as creating, dropping, or altering tables, temporarily exclude other users from those tables, but queries that only access tables elsewhere in the database can proceed.
Sybase IQ keeps your database consistent during these concurrent operations by maintaining multiple versions of table data. To understand this approach, see Chapter 10, “Transactions and Versioning.”
