What is the best practice ? (beginner question)

[k33g]

Hello
I wish I knew what was best if I make an application with Express (for example) :

• i need a "model"
• i need to save each instance of model

do I have to, every time I save, do a :

var mystore = nStore.new("data/blog.db", function() {
    mystore.save(null, myModel, function(err, key){ ... });
});

or I declare, initially, a global variable (for example) then I use in my modelsUndo edits :

global.blogStore = nStore.new("data/blog.db", function() {
    app.get('/add',function(req, res){

        var model_from_client = JSON.parse(req.param("model", null));       
        var post = new Post(model_from_client.title, model_from_client.message);

        post.save(function(key){
            console.log("Post added with key : ", key)
        });

    });

    app.listen(3000);
    console.log('Express app started on port 3000');    
});

and with :

var Post = function (title, message) {
    this.title = title ? title : "";
    this.message = message ? message : "";

    this.save = function(callback) {
        blogStore.save(null,this,function(err, key){
            callback(key, err);
        });
    }
}

thank you