Глоссарий терминов Oracle
Перевод лево-коррелированный подзапрос
Описание REF takes as its argument a correlation variable (table alias) associated with a row of an object table or an object view. A REF value is returned for the object instance that is bound to the variable or row. Subqueries so used can employ correlation variables, but only those defined within the subquery itself, not outer references. Outer references (left-correlated subqueries") are allowed only in the FROM clause of a SELECT statement."