Using db.open with MongoDB and Nodejs

Question

I have two questions.

First, the MongoDB documentation constantly refers to using db.open() and then db.collection(), but i have noticed that i'm still able to work with the api even without first calling db.open(). Is it safe to do so? Is the api internally calling db.open()?

http://mongodb.github.com/node-mongodb-native/api-generated/db.html#collection

Second, is there a param in the db object that specifies if db.open() was called? If not, how else could i find out if db.open() was called?

The reasoning is because i have built several functions that communicate with mongo, but when some of the functions interact with each other, i get errors that the database cant be 'opened' multiple times.

EDIT

I found this param in the db object. It appears this is a bool determining the use of the db.open() but im not 100% sure, does anyone know? db.serverConfig.internalMaster

christkv · Accepted Answer · 2012-05-07 07:37:38Z

5

if you need to know if a db object is connected you can check db._state == 'connected' or db.serverConfig.isConnected().

You are probably better of actually passing in a known connected object to your mvc, ensuring the db is opened before you boot up the application.

answered May 7, 2012 at 7:37

christkv

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cnotethegr8 Over a year ago

Perfect, thanks! Also is it okay if i dont call db.open() and db.close()? Will this happen on its own? It seems that the api still works without calling db.open().

Martin · Accepted Answer · 2012-05-06 22:07:46Z

1

The reasoning is because i have built several functions that communicate with mongo, but when some of the functions interact with each other, i get errors that the database cant be 'opened' multiple times.

You should reuse the db object instead of opening it multiple times - the same should be done with collection objects as there is a cost associated with creating them.

answered May 6, 2012 at 22:07

Martin

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cnotethegr8 Over a year ago

Yes, im familiar with both of these statements, but my code is in an mvc type structure. So because of this, in the controller where im actually calling the functions, it knows nothing about db.open() and db.collection(), all it knows is doThis(). This is why i would like to know a way to figure out if db.open() was called, so i can properly nest the controllers functions.

rasmeister · Accepted Answer · 2013-10-24 20:10:33Z

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I'm using a javascript driver, and it uses an 'openCalled' boolean property directly off the db object. Referencing it is as simple as

if (!db.openCalled) { //open database }

answered Oct 24, 2013 at 20:10

rasmeister

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