node.js - Mongoose :如何插入单个子文档 - 而不是数组

Question

在 mongoose 中，您可以按照以下方式为子文档声明模式:

        var childSchema = new mongoose.Schema({ name: String, age: String });
        var parentSchema = new mongoose.Schema({
            children: [childSchema]
        });
        var Parent = mongoose.model('Parent', parentSchema);
        var Child = mongoose.model('Child', childSchema);

        var child = new Child({name:'Joe', age: '21'});
        var parent = new Parent();

        parent.children = [child];

        parent.save(function(err, saved) {
            if(err) console.error(err);
        });

似乎子文档类型需要是一个数组。我需要能够将子文档保存为单个实例，而不是数组，即:

        var childSchema = new mongoose.Schema({ name: String, age: String });
        var parentSchema = new mongoose.Schema({
            children: childSchema // not an array
        });
        var Parent = mongoose.model('Parent', parentSchema);
        var Child = mongoose.model('Child', childSchema);

        var child = new Child({name:'Joe', age: '21'});
        var parent = new Parent();

        parent.children = child; // not an array

        parent.save(function(err, saved) {
            if(err) console.error(err);
        });

所以不是数组或引用，只是单个实例子文档。这可能吗？如果不是，我应该使用:

var childInstance = child.toObject();

Answer 1

有时很难看得很清楚。您不需要另一个模式来实现您想要的。您可以像这样简单地在父架构中定义子文档:

    var parentSchema = new mongoose.Schema({
        child: { 'name' : String, 'age' : Number }  // not an array, just a sub document
    });
    var Parent = mongoose.model('Parent', parentSchema);

    var parent = new Parent();
    parent.child.name = "Joe";
    parent.child.age  = 13;

    parent.save(function(err, saved) {
        if(err) console.error(err);
    });