Sybase Adaptive Server Anywhere Reference page 176

Introduction to database options
Setting temporary
options
Setting public options
158
Some options (such as COMMIT behavior) are database-wide in scope.
Setting these options requires DBA permissions. Other options (such as
ISOLATION_LEVEL) can also be applied to just the current connection,
and need no special permissions.
Changes to option settings take place at different times, depending on the
option. Changing a global option such as RECOVERY_TIME takes place
the next time the server is started.
Options that affect the current connection only generally take place
immediately. You can change option settings in the middle of a transaction,
for example. One exception to this is that changing options when a cursor is
open can lead to unreliable results. For example, changing
DATE_FORMAT may not change the format for the next row when a cursor
is opened. Depending on the way the cursor is being retrieved, it may take
several rows before the change works its way to the user.
Adding the TEMPORARY keyword to the SET OPTION statement changes
the duration of the change. Ordinarily an option change is permanent. It will
not change until it is explicitly changed using the Set Option statement.
When the SET TEMPORARY OPTION statement is executed, the new
option value takes effect only for the current connection, and for the duration
of the connection.
When the SET TEMPORARY OPTION is used to set a PUBLIC option, the
change is in place for as long as the database is running. When the database
is shut down, temporary options for the PUBLIC user ID revert back to their
permanent value.
Setting an option for the PUBLIC user ID temporarily offers a security
advantage. For example, when the LOGIN_MODE option is enabled the
database relies on the login security of the system on which it is running.
Enabling it temporarily means that a database relying on the security of a
Windows NT domain will not be compromised if the database is shut down
and copied to a local machine. In this case, the LOGIN_MODE option will
revert to its permanent value, which could be Standard, a mode where
integrated logins are not permitted.
DBA authority is required to set an option for the PUBLIC user ID.
Changing the value of an option for the PUBLIC user ID sets the value of
the option for all users who have not SET their own value. An option value
cannot be set for an individual user ID unless there is already a PUBLIC
user ID setting for that option.