PLS-00509：Implementation Restriction

错误原因：Illegal syntax was used to call a parameter-less function that returns a record or a PL/SQL table of records. When calling a function that takes parameters and returns a record, you use the following syntax to reference fields in the record: function_name(parameters).field_name However, you cannot use the syntax above to call a parameter-less function because PL/SQL does not allow empty parameter lists. That is, the following syntax is illegal: function_name().field_name -- illegal; empty parameter list You cannot just drop the empty parameter list because the following syntax is also illegal: function_name.field_name -- illegal; no parameter list.