The VALUES clause also includes a casting function for the user-specified value of the OID column because the value must be cast into the REFERENCE type of the target table.
We can mix variables passed by value and by reference easily within the use clause, and they will be handled without any problem.
我们可以将按值和按引用传递的变量轻松地混合到 use 子句中，并且可以顺利地处理这些变量。
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The REF USING INTEGER clause specifies that the INTEGER data type will be used to represent the REFERENCE type of this structured type and all of its subtypes.
REF USING INTEGER 子句指定了 INTEGER 数据类型，将使用这个数据类型表示该结构化类型及其所有子类型的 REFERENCE 类型。