如何访问本地 scope 中的全局变量？

Question

I am unable to access the global req_no and request_id variables inside sql.query blocks. As a result the second query is sending empty values of req_no and request_id.

I want to get the request_id, generate the req_no and update the req_no back to the db. How do i implement this whole setup??

router.route("/new").post((req, res) => {

  console.log(req.body);
  const request_zone = req.body.request_zone;
  const request_type = req.body.request_type;
  const requester_type = req.body.requester_type;
  const new_shipping_point = req.body.new_shipping_point;
  const request_flow = req.body.request_flow;
  const sales_order = req.body.sales_order;
  const old_value = req.body.old_value;
  const new_value = req.body.new_value;
  const requester_email = req.body.requester_email;
  const quotation = req.body.quotation;
  const request_reason = req.body.request_reason;
  const request_status = 1;
  const creation_date = null;
  const updation_date = null;
  const bot_status = "";
  const bot_comments = "";
  var req_no = "";
  const StatusFlag = 1;
  var request_id = "";
  const additional_notification_to = "";
  const additional_information = "";
  const approver = "";

  sqQuery =
    "insert into Request_Details " +
    "OUTPUT inserted.[Request_id] "+
    "values('" +
    req_no +
    "'," +
    request_zone +
    "," +
    request_type +
    "," +
    requester_type +
    "," +
    request_flow +
    ",'" +
    sales_order +
    "','" +
    requester_email +
    "','" +
    quotation +
    "'," +
    request_reason +
    "," +
    request_status +
    "," +
    creation_date +
    "," +
    updation_date +
    "," +
    StatusFlag +
    ",'" +
    bot_status +
    "','" +
    bot_comments +
    "','"+
    additional_notification_to +
    "','"+
    additional_information + 
    "','"+
    approver+
    "')";
  console.log(sqQuery);
  sql.query(connectionString, sqQuery, (err, rows) => {
    if (err != null) {
      console.log(err);
    } else {
      // console.log(rows);
      // console.log("DB Connected");
      request_id = rows[0].Request_id
      req_no = "REQ000" + request_id;
      console.log(rows);
      res.json("Data successfully added in Request Details Table");

      console.log(request_id);
      console.log(req_no);
    }
  });
  
  sqQuery=
        "update Request_Details set req_no='"+
        req_no +
        "' where request_id = " +
        request_id;
  console.log(sqQuery);
  sql.query(connectionString, sqQuery, (err, rows) => {
        if (err != null) {
          console.log(err);
        } else {
          // console.log(rows);
          // console.log("DB Connected");
          console.log("request number"+  req_no +" updated");
          res.json("Data successfully added in Request Details Table");
        }
  });

Answer 1

The simplest way to use your current sql library is to just nest the queries:

router.route("/new").post((req, res) => {
    ....
    sql.query(connectionString, sqQuery1, (err, rows1) => {
       if (err) {
           console.log(err);
           res.sendStatus(500);
           return;
       }

       // prepare second query here using results of first

       sql.query(connectionString, sqQuery2, (err, rows2) => {
           if (err) {
               console.log(err);
               res.sendStatus(500);
               return;
           }
           
           // process second query results and build response

           res.json(...);
       });

    });
});

This way the second query doesn't start until the first query is done and can use its results in preparing the second query. Also, note you need error handling to log the error, send an error response and stop further processing after each query.