ORA-30728: maximum number of columns exceeded
Cause: Adding referential constraint on a REF column requires the the creation of an additional column.
Action: Drop some columns and retry the operation.

ORA-30729: maximum number of columns exceeded
Cause: Adding scope or referential constraint on a REF column requires the creation of additional columns if the target table s object identifier is primary key based.
Action: Drop some columns and retry the operation.

ORA-02257: maximum number of columns exceeded
Cause: The number of columns in the key list exceeds the maximum number.
Action: Reduce the number columns in the list.