[英]How to give a nested table as a default parameter?
I have a function that take a nested table and integer as parameter.我有一个将嵌套表和整数作为参数的函数。
I can create any default argument for the integer paramater.我可以为整数参数创建任何默认参数。 But for the nested table, I can give only an empty table.
但是对于嵌套表,我只能给出一个空表。
function a return packageName.tOfmyrecord(i in integer:=2,j in integer:=2, k in tableofmyrecord2 package.n) PIPELINED
is
begin
--do its work
end
PLS-00653: aggregate/table functions are not allowed
PLS-00653: 不允许聚合/表函数
I want to give as a default parameter the result of the function b which return a nested table.我想将返回嵌套表的函数 b 的结果作为默认参数。 This solution works.
此解决方案有效。 But it's cumbersome.
但是很麻烦。 How can I do better?
我怎样才能做得更好?
function a return packageName.tOfmyrecord PIPELINED
is
c packageName.myrecord;
m_cur SYS_REFCURSOR;
begin
OPEN m_cur FOR select * from table(
packageName.a(2,2, packageName.b)); --I give the 3 default parameters. 2,2 for the integer and the table returns by the funciton b
loop
fetch m_cur into c;
exit when m_cur%notfound;
PIPE ROW(c);
end loop;
close m_cur;
end;
I've tried this solution too but it does'nt work.我也试过这个解决方案,但它不起作用。 Maybe there is only a little bit to change so that it works-
也许只有一点点改变才能让它起作用——
function a return packageName.a PIPELINED
is
begin
return packagename(2,2,packagename.b);
end;
PLS_00633: return statement in a pipelined function cannot contain an expression.
PLS_00633:流水线函数中的 return 语句不能包含表达式。
Create the collection type in an SQL scope:在 SQL 范围内创建集合类型:
CREATE TYPE stringlist IS TABLE OF VARCHAR2(20);
Then you can use it in SQL statements and in PL/SQL (whereas, if you define the collection in a PL/SQL scope then you can only use it in PL/SQL).然后您可以在 SQL 语句和 PL/SQL 中使用它(而如果您在 PL/SQL 范围内定义集合,那么您只能在 PL/SQL 中使用它)。
Then you can define your package specification:然后你可以定义你的包规范:
CREATE PACKAGE test_package IS
FUNCTION test_fn(
a IN INTEGER DEFAULT 1,
b IN stringlist DEFAULT stringlist('a','b','c')
) RETURN stringlist PIPELINED;
END;
/
And package body:和包体:
CREATE PACKAGE BODY test_package IS
FUNCTION test_fn(
a IN INTEGER DEFAULT 1,
b IN stringlist DEFAULT stringlist('a','b','c')
) RETURN stringlist PIPELINED
IS
BEGIN
IF b IS NULL THEN
RETURN;
END IF;
FOR i IN 1 .. b.COUNT LOOP
PIPE ROW ( b(i) || a );
END LOOP;
END;
END;
/
And use it in SQL with the default arguments:并使用默认参数在 SQL 中使用它:
SELECT *
FROM TABLE( test_package.test_fn() );
Which outputs:哪些输出:
\n|| COLUMN_VALUE |
COLUMN_VALUE |\n|
| :----------- |
:----------- |\n|
| a1 |
a1 |\n|
| b1 |
b1 |\n|
| c1 |
c1 |\n
Or provide your own arguments:或者提供你自己的论点:
SELECT *
FROM TABLE(
test_package.test_fn(
b => stringlist('d','e','f','g')
)
);
Which outputs:哪些输出:
\n|| COLUMN_VALUE |
COLUMN_VALUE |\n|
| :----------- |
:----------- |\n|
| d1 |
d1 |\n|
| e1 |
e1 |\n|
| f1 |
f1 |\n|
| g1 |
g1 |\n
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