CODEWITHSUNDEEP
node.jsmongodb
ooouuiii
ooouuiii

Reputation: 319

Call function in document insert

I am trying to create "server side function" (custom JS function loaded in Mongo db) according to autoincrement tutorial. The main idea is to have function getNextSequence(collectionName), which returns autoincrement id for this collection. Trick is to have separate collection "counters" with document for each collection, that holds autoincrement status.

Anyway, I have created and loaded that function in Mongo and it works nicely via Mongo shell:

db.users.insert(
   {
     _id: getNextSequence("userid"),
     name: "Sarah C."
   }
)

It also works from NodeJS via eval:

db.eval('getNextSequence(\'test\')', function(err, result){...});

But I can't figur out, how to use it inline in document when inserting from NodeJS. I cannot write: 

   {
     _id: getNextSequence("userid"),
     name: "Sarah C."
   }

as this would expect getNextSequence to be NodeJs method. Is there any expression form in NodeJS+MongoDB for this? Thanks!

Upvotes: 1

Views: 1924

Answers (2)

TMan
TMan

Reputation: 1905

You'll need to call it in node the way you have specified above and then use the value that is returned in your insertion.

db.eval('getNextSequence(\'test\')', function(err, result) {
  db.users.insert({
      _id: result,
      name: "John Doe"
      ...
    }, function(err, result) {
         ...
    }})
});

For cleaner syntax, you could try using the npm package mongo-triggers:

https://www.npmjs.org/package/mongo-triggers

Upvotes: 1

Anirudh Negi
Anirudh Negi

Reputation: 177

in the post method set a variable which requires db:
var db = req.db;
Then declare a variable for your db collection:
var collection = db.get('counter');
then insert your items:

    collection.insert({
        _id: getNextSequence("userid"),
         name: "Sarah C."
         }, function (err, doc) {
             if (err) {
               // DO SOMETHING
             }
             else {
               // DO SOMETHING
             }
      });

Upvotes: 1

Related Questions