Rules for Using the ROWID Keyword in a Join Index Definition
The ROWID keyword can only be used in a join index definition.
You can optionally specify ROWID for a base table in the select list of a join index
definition. For a column-partitioned join index, the ROWID for the base table in the
select list of the join index definition is required.
If you reference multiple tables in the join index definition, then you must fully
qualify each ROWID specification.
You can reference an alias name for ROWID, or the keyword ROWID itself if no correlation
name has been specified for it, in the primary index definition or in a secondary
index defined for the join index in its index clause.
This does not mean that you can reference a ROWID or its alias in a secondary index defined separately
with a CREATE INDEX statement (see CREATE INDEX in SQL Data Definition Language) after the join index has been created.
An alias is required for ROWID if the join index is column partitioned.
If you reference a ROWID alias in the select list of a join index definition, then
you can also reference that alias in a CREATE INDEX statement that creates a secondary
index on the join index.
Aliases are required to resolve any column name or ROWID ambiguities in the select
list of a join index definition.
An example is the situation where you specify ROWID for more than one base table in
the index definition.
Also see the description of the CREATE JOIN INDEX statement in SQL Data Definition Language.