All Sybase IQ locks occur automatically, based on the type of operation a user requests. You do not need to request a lock explicitly. The transaction that has access to the table is said to hold the lock.
When a table is locked in Sybase IQ, no other transaction can have write access to it, but any transaction can have read access to it. Data definition operations form an exception to this universal read access; see the discussion below for details. Any other write transaction that attempts to access a table with a write lock on it receives an error.
The locks maintain the reliability of information in the database by preventing concurrent access by other transactions. The database server retains all the locks acquired by a transaction until the transaction completes, due to either a commit or a rollback.
Locks in the Catalog Store are Adaptive Server Anywhere
style locks, which work differently. For information on these locks,
see the Adaptive Server Anywhere User’s Guide.
