从函数中获取并返回引用光标以进行记录 [英] fetch from function returning a ref cursor to record

问题描述

我在包装中有一个函数，该函数将REF CURSOR返回到RECORD.我试图从代码块中调用此函数.调用代码如下:

I have a function in a package that returns a REF CURSOR to a RECORD. I am trying to call this function from a code block. The calling code looks like this:

declare      
   a_record package_name.record_name; 
   cursor c_symbols is select package_name.function_name('argument') from dual;

begin 
   open c_symbols;   
   loop            
        fetch c_symbols into a_record;
        exit when c_symbols%notfound;              
   end loop;
   close c_symbols; 
end;

作为package_name一部分的函数声明看起来像这样:

The function declaration as part of package_name looks something like this:

TYPE record_name IS RECORD(
      field_a       varchar2(20);
);

TYPE record_cursor IS REF CURSOR RETURN record_name;

FUNCTION getsymbols(argument IN varchar2) return record_cursor;

当我尝试运行调用代码块时，出现异常:PLS-00386:在FETCH游标和INTO变量之间的'EXAMPLE_SYMBOLS'中发现类型不匹配.

When I try to run the calling code block, I get the exception: PLS-00386: type mismatch found at 'EXAMPLE_SYMBOLS' between FETCH cursor and INTO variables.

a_record的类型应该是什么?如何访问我要提取的(record_name类型的)记录的各个元素?

What should the type of a_record be and how can I access individual elements of the record I am fetching(of type record_name)?

推荐答案

我怀疑您认为您的光标应该从REFCURSOR获取行.它不是. REFCURSOR本身就是一个游标，您无需使用其他游标进行选择.

I suspect that you think that your cursor should be fetching rows from the REFCURSOR. It's not. The REFCURSOR is itself a cursor, you don't use another cursor to select from it.

您当前的游标正在执行的操作是获取包含函数调用结果的单行单列.这是一个record_cursor而不是record_name，因此您会遇到类型不匹配的情况.

What your current cursor is doing is fetching a single row, with a single column, containing the result of the function call. Which is a record_cursor not a record_name, so you get a type mismatch.

我怀疑您真正想做的事情是这样的:

I suspect what you really want to do is something like this:

declare
  symbol_cursor  package_name.record_cursor;
  symbol_record  package_name.record_name;
begin
  symbol_cursor := package_name.function_name('argument');
  loop
    fetch symbol_cursor into symbol_record;
    exit when symbol_cursor%notfound;

    -- Do something with each record here, e.g.:
    dbms_output.put_line( symbol_record.field_a );

  end loop;

  CLOSE symbol_cursor;

end;

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