Mongoose auto increment

According to this mongodb article it is possible to auto increment a field and I would like the use the counters collection way.

The problem with that example is that I don't have thousands of people typing the data in the database using the mongo console. Instead I am trying to use mongoose.

So my schema looks something like this:

var entitySchema = mongoose.Schema({
  testvalue:{type:String,default:function getNextSequence() {
        console.log('what is this:',mongoose);//this is mongoose
        var ret = db.counters.findAndModify({
                 query: { _id:'entityId' },
                 update: { $inc: { seq: 1 } },
                 new: true
               }
        );
        return ret.seq;
      }
    }
});

I have created the counters collection in the same database and added a page with the _id of 'entityId'. From here I am not sure how to use mongoose to update that page and get the incrementing number.

There is no schema for counters and I would like it to stay that way because this is not really an entity used by the application. It should only be used in the schema(s) to auto increment fields.

---

下面是一个例子，您可以如何在Mongoose中实现自动增量字段：

var CounterSchema = Schema({
    _id: {type: String, required: true},
    seq: { type: Number, default: 0 }
});
var counter = mongoose.model('counter', CounterSchema);

var entitySchema = mongoose.Schema({
    testvalue: {type: String}
});

entitySchema.pre('save', function(next) {
    var doc = this;
    counter.findByIdAndUpdate({_id: 'entityId'}, {$inc: { seq: 1} }, function(error, counter)   {
        if(error)
            return next(error);
        doc.testvalue = counter.seq;
        next();
    });
});

---

You can use mongoose-auto-increment package as follows:

var mongoose      = require('mongoose');
var autoIncrement = require('mongoose-auto-increment');

/* connect to your database here */

/* define your CounterSchema here */

autoIncrement.initialize(mongoose.connection);
CounterSchema.plugin(autoIncrement.plugin, 'Counter');
var Counter = mongoose.model('Counter', CounterSchema);

You only need to initialize the autoIncrement once.

---

The most voted answer doesn't work. This is the fix:

var CounterSchema = new mongoose.Schema({
    _id: {type: String, required: true},
    seq: { type: Number, default: 0 }
});
var counter = mongoose.model('counter', CounterSchema);

var entitySchema = mongoose.Schema({
    sort: {type: String}
});

entitySchema.pre('save', function(next) {
    var doc = this;
    counter.findByIdAndUpdateAsync({_id: 'entityId'}, {$inc: { seq: 1} }, {new: true, upsert: true}).then(function(count) {
        console.log("...count: "+JSON.stringify(count));
        doc.sort = count.seq;
        next();
    })
    .catch(function(error) {
        console.error("counter error-> : "+error);
        throw error;
    });
});

The options parameters gives you the result of the update and it creates a new document if it doesn't exist. You can check here the official doc.

And if you need a sorted index check this doc

链接地址: http://www.djcxy.com/p/60692.html

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