Oracle Apex 20.1 错误：处理验证时出错

Question

I am trying to create a validation for a page in an application on oracle apex. Below is the pl/sql function body (returning boolean) I have:

declare v_equipid integer;
begin
        SELECT count(*) into v_equipid from equipment
        WHERE equipstatus = 'available' and equipID = :P3_EquipID;

    if v_equipid = 1 then
        return true;
    else
        return false;
    end if;
end; 

It is used to check whether the EquipID submitted has equipstatus = 'available'. After I run the application and submit the form, it gives the following error:

Error: Error processing validation.

• is_internal_error: true
• is_common_runtime_error: false
• apex_error_code: APEX.VALIDATION.UNHANDLED_ERROR
• ora_sqlcode: -6502
• ora_sqlerrm: ORA-06502: PL/SQL: numeric or value error ORA-06512: at "APEX_200100.WWV_FLOW_VALIDATION", line 846 ORA-06512: at "APEX_200100.WWV_FLOW_VALIDATION", line 846
• error_backtrace: ORA-06512: at "APEX_200100.WWV_FLOW_VALIDATION", line 846 ORA-06512: at "APEX_200100.WWV_FLOW_VALIDATION", line 846 ORA-06512: at "APEX_200100.WWV_FLOW_VALIDATION", line 1029

I don't know how to fix this and I would appreciate your help. Thank you in advance!

Answer 1

Numeric or value error, eh?

This is what might be causing the problem:

and equipID = :P3_EquipID;

What is equipID 's datatype? If it is a NUMBER , try

and equipID = to_number(:P3_EquipID);

---

As that's not the case (as you commented), would this help?

declare 
  v_equipid number;
begin
  SELECT count(*) 
    into v_equipid 
    from equipment
    WHERE equipstatus = 'available' 
      and equipID = :P3_EquipID;

  return v_equipid = 1;
end; 

Answer 2

The key to developing in apex is debugging your own code. That takes a bit of getting used to. Research on how to debug your apex app and instrument your pl/sql code, there is plenty of documentation available on the web.

You could just debug the validation by running that pl/sql in SQL workshop. Replace your RETURN TRUE/FALSE statements with dbms_output.put_line('true/false') to get the result. Running it in sql workshop will give you the exact line number. ORA-06502 usually means that a variable or column of type NUMBER is assigned a value of datatype VARCHAR2 (or another datatype that cannot be casted back to a number).

Make sure you remove the dbms_output statements again when you move the code back to apex.

You could also debug your process in apex itself by using apex_debug, have a look at the documentation for a full overview of the functionality, something like this:

DECLARE
  v_equipid NUMBER; --integer is deprecated, should not be used
BEGIN
  -- put double quotes around the %0 to make any trailing/leading characters visible.
  apex_debug.info(
      p_message => 'Start of validation,  P3_EQUIPID = "%0"',
      p0        => :P3_EQUIPID);
  SELECT COUNT(*)
    INTO v_equipid
    FROM equipment
   WHERE equipstatus = 'available' AND
         equipid = :P3_EQUIPID;
  apex_debug.info(
      p_message => 'After SELECT INTO,  v_equipid = "%0"',
      p0        => v_equipid);
  IF v_equipid = 1 THEN
    RETURN true;
  ELSE
    RETURN false;
  END IF;
END;

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