Restrictions

In an OPM schema containing object classes associated with versioned attributes, the following restrictions must be satisfied:

1. identifier attributes cannot be versioned attributes;

2. a non-versioned abstract attribute can refer only to generic objects;

3. a non-versioned abstract attribute cannot be specified as an inverse of a versioned attribute; a versioned abstract attribute cannot be specified as an inverse of another attribute;

4. derivation for non-versioned arithmetic or aggregate function derived attributes can consist of only non-versioned local attributes of , and derivation for versioned arithmetic or aggregate function derived attributes can consist of only versioned local attributes of ;

5. abstract attributes referencing foreign classes can be versioned, but can have only generic references to foreign classes.