Oracle EBS interface development - quick generation of JSON format data

When it comes to interface development , If many fields or complex nested structures are involved , In order to avoid artificial patchwork json data , Here are some common json How data is generated .

plug-in unit pljson The way

Avoid Chinese Unicode transformation

modify ：pljson_printer.escapeChar as follows ：

function escapeChar(ch char) return varchar2 deterministic is
     result varchar2(20);
  begin
      --backspace b = U+0008
      --formfeed f = U+000C
      --newline n = U+000A
      --carret r = U+000D
      --tabulator t = U+0009
      result := ch;

      case ch
      when chr( 8) then result := '\b';
      when chr( 9) then result := '\t';
      when chr(10) then result := '\n';
      when chr(12) then result := '\f';
      when chr(13) then result := '\r';
      when chr(34) then result := '\"';
      when chr(47) then if (escape_solidus) then result := '\/'; end if;
      when chr(92) then result := '\\';
      /* WARNING: ascii() returns PLS_INTEGER and large unicode code points can be negative */
      else /*if (ascii(ch) >= 0 and ascii(ch) < 32) then result := '\u' || replace(substr(to_char(ascii(ch), 'XXXX'), 2, 4), ' ', '0'); elsif (ascii_output) then result := replace(asciistr(ch), '\', '\u'); end if;*/ [email protected]  Avoid transcoding Chinese 
        null;
      end case;
      return result;
  end;

Print directly

Although the table field type is varchar2 type , But if the stored values are all numbers , Will be automatically converted to number Format , That is, there are no double quotes , You can add single quotation marks , Then replace the single quotation marks to avoid this implicit conversion .

declare
   ret     pljson_list;
   dyn_ref sys_refcursor;
begin
   open dyn_ref for
      select h.BATCH_NO,
             h.INVOICE_TYPE,
             h.SEQ,
             h.DOC_SEQUENCE_NUM,
             h.DOC_NUM,
             h.DOC_TYPE,
             h.APPROVE_EMPLOYEE_NO,
             h.MAKER_EMPLOYEE_NO,
             h.REQUESTOR_NO,
             h.CURRENCY_CODE,
             h.CURRENCY_CODE_BEG,
             h.EXCHANGE_RATE,
             h.VENDOR_NUM,
             h.PAY_FLAG,
             to_char(h.GL_DATE,'YYYY-MM-DD') GL_DATE,
              to_char(h.BUSINESS_DATE,'YYYY-MM-DD') BUSINESS_DATE,
             h.PREPAYMENT_FLAG,
             h.INVOICE_AMOUNT,
             h.INVOICE_AMOUNT_BEG,
             h.SIG_FLAG,
             TO_CHAR(h.FINISHED_DATE,'YYYY-MM-DD') FINISHED_DATE,
             h.PAYMENT_CURRENCY_CODE,
             /*h.ORGANIZATION_NAME,*/
             ''''||hou.short_code || '''' short_code,
             h.SOURCE_LINE_ID,
             h.CREATION_DATE,
             h.ATTRIBUTE1,
             h.ATTRIBUTE2,
             h.ATTRIBUTE3,
             h.ATTRIBUTE4,
             h.ATTRIBUTE5,
             h.ATTRIBUTE6,
             cursor (select NVL(l.LINE_NUM,0) LINE_NUM,
                            l.IFACE_TYPE,
                            l.DR_CR_DIRECTOR,
                            l.AMOUNT,
                            l.AMOUNT_BEG,
                            l.INVOICE_COMMENTS,
                            '''' || l.COA_COMPANY || '''' COA_COMPANY,
                            '''' || l.COA_DEPT || '''' COA_DEPT,
                            '''' || l.COA_ACCOUNt || '''' COA_ACCOUNT,
                            l.COA_SUB_ACCOUNT,
                            '''' ||l.COA_PRODUCT || '''' COA_PRODUCT,
                            '''' ||l.COA_PROJECT || '''' COA_PROJECT,
                            '''' ||l.COA_INTERCOMPANY || '''' COA_INTERCOMPANY,
                            to_char(l.PAYMENT_DATE,'YYYY-MM-DD') PAYMENT_DATE,
                            l.PAYMENT_AMOUNT,
                            l.PAYMENT_BANK_NUM,
                            l.VERIFICATION_AMOUNT,
                            l.VERIFICATION_AMOUNT_BEG,
                            l.VERIFICATION_DOC_NUM,
                            l.SOURCE_LINE_ID,
                            l.ATTRIBUTE1,
                            l.ATTRIBUTE2,
                            l.ATTRIBUTE3,
                            l.ATTRIBUTE4,
                            l.ATTRIBUTE5,
                            l.ATTRIBUTE6
                       from cux_ap_amt_to_ebs_iface_l l
                      where h.header_id = l.header_id
                      order by l.line_id 
                      ) item_lines
        from cux_ap_amt_to_ebs_iface_h h,hr_operating_units hou 
       where h.process_status = 'S'
       and h.organization_name = hou.name
             and h.header_id = 10149;
   ret := pljson_util_pkg.ref_cursor_to_json(dyn_ref);
   /*ret.print;*/
   dbms_output.put_line(replace(ret.to_char(true),'''',null)); 
end;

To clob The large capacity

The direct print above may exceed the print buffer setting , The following can be changed to clob The way

create or replace function ufx_plson_get_json_from_sql (i_sql in varchar2)
return clob
as
  -- Local variables here
  tstjson_list pljson_list;
  l_Result_json_clob clob;
begin
  -- Test statements here
  dbms_lob.createtemporary(l_Result_json_clob, true);

  tstjson_list := pljson_util_pkg.sql_to_json(i_sql);
  tstjson_list.to_clob(l_Result_json_clob);

  return l_Result_json_clob;
exception
  when others then raise;
end;
/
/* example */
select ufx_plson_get_json_from_sql (i_sql =>
          q'[ select sysdate, systimestamp, user from dual]') sql_result_as_json
  from dual;

oracle apex The way

cursor The way

somewhat ： You can realize nested printing

defects ： If the field is null value , Then the field is not displayed , Cannot control whether to print vacant .

DECLARE
  c sys_refcursor;
BEGIN
  open c for select deptno,
                    dname,
                    cursor(select empno,
                                  ename
                             from emp e
                            where e.deptno=d.deptno) emps
               from dept d;
  apex_json.open_object;
  apex_json. write('departments', c);
  apex_json.close_object;
END;
 
{ "departments":[
      {
   "DEPTNO":10,
       "DNAME":"ACCOUNTING",
       "EMPS":[{
   "EMPNO":7839,"ENAME":"KING"}]},
      ...
     ,{
   "DEPTNO":40,"DNAME":"OPERATIONS","EMPS":null}] }
     

WRITE_CONTEXT Procedure

advantage : adopt write_context Parameters p_write_null You can control whether to print null values
shortcoming ：If the query contains object type, collection or cursor columns, an error is raised. If the column is VARCHAR2 and the uppercase value is ‘TRUE’ or ‘FALSE’, boolean values are generated.

DECLARE
    l_context apex_exec.t_context;
begin
    l_context := apex_exec.open_query_context( 
                     p_location   => apex_exec.c_location_local_db,
                     p_sql_query  => q'#select * from dept#' );

   apex_json.open_object;
   apex_json.write_context( p_name => 'departments', p_context => l_context);
   apex_json.close_object;
 end;

{ "departments":[
     { "DEPTNO":10 ,"DNAME":"ACCOUNTING" ,"LOC":"NEW YORK" }
    ,{ "DEPTNO":20 ,"DNAME":"RESEARCH" ,"LOC":"DALLAS" } 
    ,{ "DEPTNO":30 ,"DNAME":"SALES" ,"LOC":"CHICAGO" } 
    ,{ "DEPTNO":40 ,"DNAME":"OPERATIONS" ,"LOC":"BOSTON" } ] }