如何向AttributeValueAssignment输入值:insert_update AttributeValueAssignment;& Item; attribute(& Item); attributeAssignment(classificationAttribute(code,systemVersion(catalog(id),version)),systemVersion(catalog(id),version ),classificationClass(catalogVersion(目录(ID),版本),代码))[forceWrite =真,独特=真]; systemVersion(目录(ID),版本);值(代码,systemVersion(目录(ID),版本) )[forceWrite =真,允许为空=真,独特=真];