The sharedTransientAllowed class option enables you to specify that a class can have shared transient instances. (For details, see "Adding Classes to Your Schema", in Chapter 3.)
If you uncheck the Allow Shared Transient Instances check box on the Lifetime sheet of the Define Class dialog, an exception is raised at every attempt to create a shared transient instance of the class. An error is raised if you attempt to construct a shared transient object from within a method (that is, you call create <object-name> sharedTransient).
Subclass shared transient instances are restricted according to the subclassSharedTransientAllowed class option, described later in this section.
When you create a new class, the default setting for the sharedTransientAllowed class option is determined as follows.
The default value is the same as the subclassSharedTransientAllowed option value of the immediate superclass.
If the subclassSharedTransientAllowed option of the immediate superclass is set to false, the Allow Shared Transient Instances check box on the Lifetime sheet of the Define Class dialog is disabled.