I am trying to create a database schema for the following model:
I'm not sure if the best way to represent this in MongoDb would be, but since I'm using Mongoose and there is a plugin for inheritance, I'm trying to do the following:
var mongoose = require('mongoose') , extend = require('mongoose-schema-extend') , Schema = mongoose.Schema , ObjectId = mongoose.Schema.Types.ObjectId var db = mongoose.connection; db.on('error', console.error.bind(console, 'connection error:')); db.once('open', function callback () { //Mashup and Item are bound (itemSchema is a sub-doc) var itemSchema = new Schema({ pos: { top: Number, left: Number } , size: { width: Number, height: Number } , component: { type: ObjectId, ref: 'Component' } }) var mashupSchema = new Schema({ name: String , desc: String , size: { width: Number, height: Number } , items: [itemSchema] }) var componentSchema = new Schema({ name: String , desc: String }, { discriminatorKey : '_type' }) var imageComponentSchema = componentSchema.extend({ url: String }) var textComponentSchema = componentSchema.extend({ text: String }) var htmlComponentSchema = componentSchema.extend({ html: String }) var webComponentSchema = componentSchema.extend({ page: { type: ObjectId, ref: 'Page' } , selector: { type: ObjectId, ref: 'Selector' } }) var pageSchema = new Schema({ name: String , desc: String , url: String , active: { type: Boolean, default: false } , webComponents: [{ type: ObjectId, ref: 'WebComponent' }] }) var selectorSchema = new Schema({ desc: String , url: String , cssPath: String }) ///MODELS var Mashup = db.model("Mashup", mashupSchema) var Component = db.model("Component", componentSchema) var ImageComponent = db.model("ImageComponent", imageComponentSchema) var TextComponent = db.model("TextComponent", textComponentSchema) var HtmlComponent = db.model("HtmlComponent", htmlComponentSchema) var WebComponent = db.model("WebComponent", webComponentSchema) var Page = db.model("Page", pageSchema) var Selector = db.model("Selector", selectorSchema) //CREATE //a new empty mashup //var aMashup = new Mashup({ name: "Test" }); Mashup.create({ name: "Test" }, function (err, mashup) { if (err) return console.log("Saved: empty mashup") //mashup saved, create a webComponent var aWebComponent = new WebComponent({ name: "Map", desc: "A map" }) //create a page var aPage = new Page({ name: "Maps", desc: "Google Maps", url: "http://maps.google.com" }) aPage.webComponents.push(aWebComponent) aWebComponent.page = aPage //create a selector var aSelector = new Selector({desc: "Just the map", url: "maps.google.com", cssPath: "#map" }) aWebComponent.selector = aSelector //save the component aWebComponent.save(function(err) { if (err) return console.log("Saved: WebComponent") aPage.save(function(err) { if (err) return console.log("Saved: the Page") aSelector.save(function(err) { if (err) return console.log("Saved: the Selector") //finally add the item with the new component var item = { pos: { top:6, left:10 }, size: { width:100, height:100}, component: aWebComponent } mashup.items.push(item) mashup.save(function (err) { if (err) return console.log("Saved: mashup with item (WebComponent with Page and Selector)") //POPULATE Mashup .find({}) .populate("items.component") .exec(function (err, mashup) { if (err) console.log(err) console.log(mashup); }) }) }) }) }) }) });
This is a use case when a user creates a Mashup and then adds a new element to it, creating a new WebComponent. I need this Item class because every other mashup must have “instances” (i.e. Elements) of existing Components.
Now I'm new to Mongoose, and I'm sure everything can be done differently. Any suggestion is welcome here. However, when I try to request filling in Mashups, the result I get is the following:
Saved: empty mashup Saved: WebComponent Saved: the Page Saved: the Selector Saved: mashup with item (WebComponent with Page and Selector) [ { __v: 1, _id: 520a8aae3c1052f723000002, name: 'Test', items: [ { component: null, _id: 520a8aaf3c1052f723000006, size: [Object], pos: [Object] } ], size: {} } ]
component must be populated, but it is not. I think this is because it expects a component while it receives a WebComponent . How to fix it? Should I stop trying with inheritance? What other methods exist for creating a database schema for this model?