oracle - PL/SQL中如何查看变量的类型？

Question

PL/SQL 中是否有函数可以显示变量的确切类型，如 SQL 中的 DUMP 函数？

我尝试过以下方法

DECLARE
   l_variable   INTEGER := 1;
BEGIN
   DBMS_OUTPUT.PUT_LINE (DUMP (l_variable));
END;

但它给出了以下错误:

PLS-00204: function or pseudo-column 'DUMP' may be used inside a SQL statement only

Answer 1

您可以使用 PL/Scope 创建此函数。但它不适用于匿名 block ，并且您需要将变量作为字符串引用。

create or replace function get_plsql_type_name
(
    p_object_name varchar2,
    p_name varchar2
) return varchar2 is
    v_type_name varchar2(4000);
begin
    select reference.name into v_type_name
    from user_identifiers declaration
    join user_identifiers reference
        on declaration.usage_id = reference.usage_context_id
        and declaration.object_name = reference.object_name
    where
        declaration.object_name = p_object_name
        and declaration.usage = 'DECLARATION'
        and reference.usage = 'REFERENCE'
        and declaration.name = p_name;

    return v_type_name;
end;
/

示例:

alter session set plscope_settings = 'IDENTIFIERS:ALL';

create or replace type my_weird_type is object
(
    a number
);

create or replace procedure test_procedure is
    var1 number;
    var2 integer;
    var3 my_weird_type;
    subtype my_subtype is pls_integer range 42 .. 43;
    var4 my_subtype;
begin
    dbms_output.put_line(get_plsql_type_name('TEST_PROCEDURE', 'VAR1'));
    dbms_output.put_line(get_plsql_type_name('TEST_PROCEDURE', 'VAR2'));
    dbms_output.put_line(get_plsql_type_name('TEST_PROCEDURE', 'VAR3'));
    dbms_output.put_line(get_plsql_type_name('TEST_PROCEDURE', 'VAR4'));
end;
/

begin
    test_procedure;
end;
/

NUMBER
INTEGER
MY_WEIRD_TYPE
MY_SUBTYPE