I have a Bookshelf.js model. I want to be able to set and get attributes for this model that are not persistent in the database.
For instance lets say I have a model that looks like this:
var Domain = bookshelf.Model.extend({
tableName: 'domains',
initialize: function() {
this.on('creating', this.setDomainName);
},
setDomainName: function() {
this.set('name', getDomainFromUrl(this.url));
}
});
With a schema that looks like this:
knex.schema.createTable('domains', function (table) {
table.increments().index();
table.text('name').index();
table.timestamps();
});
I want to be able to save an attribute called url, then later parse the url into a domain before it saves.
When I try something like this:
new Domain({url: 'http://someurl.com/foo/bar'}).save()
I get the error message:
"column \"url\" of relation \"domains\" does not exist"
I've looked and looked. I cant find any way to add non-persistent attributes to a bookshelf.js model. I also couldn't find anything about adding custom getter and setter methods to a bookshelf.js model.
Any help or insight is appreciated!
On my phone, so forgive the short reply, but what you want is called 'virtual' or 'composite' fields.
https://github.com/tgriesser/bookshelf/wiki/Plugin:-Virtuals
Every database mapper has them, but when you don't know what they're called it's understandably difficult to google a solution.
Related
I have a doc in couchDB:
{
"id":"avc",
"type":"Property",
"username":"user1",
"password":"password1",
"server":"localhost"
}
I want to write a view that returns a map of all these fields.
The map should look like this: [{"username","user1"},{"password","password1"},{"server","localhost"}]
Here's pseudocode of what I want -
HashMap<String,String> getProperties()
{
HashMap<String,String> propMap;
if (doc.type == 'Property')
{
//read all fields in doc one by one
//get value and add field/value to the map
}
return propMap;
}
I am not sure how to do the portion that I have commented above. Please help.
Note: right now, I want to add username, password and server fields and their values in the map. However, I might keep adding more later on. I want to make sure what I do is extensible.
I considered writing a separate view function for each field. Ex: emit("username",doc.username).
But this may not be the best way to do this. Also needs updates every time I add a new field.
First of all, you have to know:
In CouchDB, you'll index documents inside a view with a key-value pair. So if you index the property username and server, you'll have the following view:
[
{"key": "user1", "value": null},
{"key": "localhost", "value": null}
]
Whenever you edit a view, it invalidates the index so Couch has to rebuild the index. If you were to add new fields to that view, that's something you have to take into account.
If you want to query multiple fields in the same query, all those fields must be in the same view. If it's not a requirement, then you could easily build an index for every field you want.
If you want to index multiple fields in the same view, you could do something like this:
// We define a map function as a function which take a single parameter: The document to index.
(doc) => {
// We iterate over a list of fields to index
["username", "password", "server"].forEach((key, value) => {
// If the document has the field to index, we index it.
if (doc.hasOwnProperty(key)) {
// map(key,value) is the function you call to index your document.
// You don't need to pass a value as you'll be able to get the macthing document by using include_docs=true
map(doc[key], null);
}
});
};
Also, note that Apache Lucene allows to make full-text search and might fit better your needs.
I am building an app which will load a JSON file and use that to populate all models. I have to keep a list of changes and then post this back to the server after a 'publish' button is clicked.
I think a combination of using Backbone.LocalStorage and using model change events to then track which models have changes sounds right but it'd help to hear from someone who's gone down this route or solved similar!
Does this approach makes sense? Is there a better one?
If you are trying to track individual changes and not just the final state before saving, then it is probably a good idea to create an Audit model or something similar. You can hook into the change events as you suggested. Saving those Audit models to the server can be done using the standard version (or some batched modification) of Backbone.sync whenever you want. That model might look something like this:
var Audit = Backbone.Model.extend({
defaults : {
auditableType: "", auditableId: null, auditedChanges : ""
},
paramRoot : "audit"
});
var Audits = Backbone.Collection.extend({
model : Audit
});
Then create a Model prototype that all audited models can extend from:
var audits = new Audits();
var AuditedModel = Backbone.Model.extend({
initialize : function (options) {
this.listenTo(this, "change", function (model, options) {
audits.add({
auditableType : this.paramRoot,
auditableId : this.id,
auditedChanges : this.changed
});
});
}
});
Now just extend from your AuditedModel for any models you want to track changes on.
var User = AuditedModel.extend({
paramRoot : "user",
// Do whatever
});
I've seen other posts in this site regarding the same issue and I've tried the solutions given. I've also visited the links that may offer a solution but I'm still stuck with the same error.
I'm using DOJO and something as simple as this won't even work
myStore.newItem({id: 'test', otherfield: 'otherinfohere'});
myStore.save();
Supposedly the "newItem() was not passed an identity for the new item" error appears when you haven't provided an identifier for the new item, which i have.
The whole purpose of this (Just in case anyone can provide a good idea or has done something similar before) is that i want to create a data grid that shows info from a particular store. The problem is, that in that store all the items may not have the same structure. For instance:
I may have a store that looks like this
{identifier: 'id',
label: 'name',
items: [
{ id:'1', name:'Ecuador', capital:'Quito' },
{ id:'2', name:'Egypt', capital:'Cairo' },
{ id:'3', name:'El Salvador', capital:'San Salvador' , additionalField: 'otherinfohere'},
{ abbr:'gq', name:'Equatorial Guinea', capital:'Malabo', additionalField: 'otherinfohere'},
]}
This is possible because I'm the one constructing the store in a Spring Controller (I'm also using the Spring Framework) from information I have locally stored in a Berkeley DB. So what i need is a data grid with a dynamic layout because I don't want blank spaces to show in the view in the rows with lesser amount of fields, and i need to show all the info in the store at the same time, but i don't know how to do this.
I thought of doing it by creating a simple layout of only 1 field. In it I would load data from a store i create dynamically at runtime. The data in the store would be composed of HTML combined with the values coming from the original store so I could obtain something like this, which is inside an attribute of a JavaScript Object and let the browser parse it for me:
<div><span>id: originalID </span>....</div>
This of course is a simple example, the html layout i'm looking for is far more complicated, but i think that passing it as a string to an object might do the trick.
The problem is that i don't even know if that idea will work because i get that error whenever i try to add values to my secondary store.
rdb.modules.monitor.historicStore.fetch({onComplete: function(items, request){
for (var i = 0; i < items.length; i++){
var item = items[i];
var obj = new Object();
obj.id = rdb.modules.monitor.historicStore.getValue(item, "id");;
var html = "<div><span>";
html += rdb.modules.monitor.historicStore.getValue(item, "sql");
html += "</span></div>";
obj.html = html;
myStore.store.newItem(obj);
}
}});
In this context "historicStore" refers to the JSON store that has the values that i need to convert and add to "myStore" after i added some HTML.
I hope you got the main idea of what I'm trying to do. If anyone can help me we either of these problems i would really appreciate it. Thanks in advance
For the issue regarding store:-
"id" is mandatory for a store, if it is going to be used for a grid(datagrid, EnhancedGrid, etc. whatever). The items are handled only on basis of "id" attribute by the grid data structures.
Usually, id can be a loop variable/ auto incrementation, to avoid any cases like you have said. Before adding the store to the grid, ensure that all items have the id attribute. You can write a function which will loop through each item and check for this, else add an auto-incrementing value for the id attribute of that item.
I’m trying to understand how and where to use data after a fetch using Backbone.js but I’m a little confused.
I’ll explain the situation.
I have an app that, on the startup, get some data from a server. Three different kind of data.
Let’s suppose Airplanes, Bikes, Cars.
To do that, I’ve inserted inside the three collections (Airplanes, Cars, Bikes) the url where to get these data.
I’ve overwrited the parse method, so I can modify the string that I get, order it, and put it in an object and inside localstorage. I need it to be persistent because I need to use those 3 data structure.
So with a fetch i get all those data and put them inside localstorage. Is it correct doing it that way?
Now i need to make other calls to the server, like “get the nearest car”.
In the view i need to see the color, name and model of the car, all that informations are inside the object “Cars” in localstorage.
In my view “showcars.view” I just call a non-backbone js, (not a collection, model or view) where i get all the informations i need. In this js i do:
var carmodel = new Car(); //car is the backbone model of the cars
carmodel.url = '/get/nearest/car'; //that give id of the nearest car
carmodel.fetch ({
success: function () {}
//here i search the Cars object for a car with the same id
//and get name, color, model and put them in sessionstorage
})
So after that call, in the view I can get the data I need from the sessionstorage.
Is that a bad way of doing things? If so, how i should fetch and analyze those informations? I should do all the calls and operations inside the models?
Thanks
This would be the way that you might implement what you want.
var Car = Backbone.Model.extend();
var Cars = Backbone.Collection.extend({
model: Car,
url: '.../cars'
});
var NearestCar = Backbone.Model.extend({
url: '...nearest/car'
});
var cars = new Cars();
var nearestCar = new NeaerestCar();
cars.fetch({
success: function() {
nearestCar.fetch({
success: function(model) {
var oneYouWant = cars.get(model.get('id'));
// do something with your car
// e.g.:
// var carView = new CarView({model: oneYouWant});
// $('body').append(carView.render().el);
});
});
});
});
In general, Backbone keeps everything in memory (that is, the browser memory) so there is no need to save everything to local storage, as long as your Collection object is somehow reachable from the scope you are sitting in (to keep things simple let's say this is the global window scope).
So in your case I will have something like three collections:
window.Cars
window.Airplanes
window.Bikes
Now you want the nearest. Assuming you are in a Backbone View and are responding to an event, in your place I would do something like this (just shows the meaningful code):
var GeneralView = Backbone.View.extend({
events: { "click .getNearestCar": "_getNearestCar" },
_getNearestCar: function () {
$.getJson('/get/nearest/car', function (data) {
// suppose the data.id is the id of the nearest car
var nearestCar = window.Cars.get(data.id)
// do what you plase with nearestCar...
});
}
});
In my app, everything I do with data is based on the primary key as the data is stored in the database. I would like to grab a model from a collection based on this key.
Using Collection.at() requires the array index, Collection.getByCid() requires the client ID that backbone randomly generates.
What is the best way to grab the model I want from the collection with the given id value? I figure the worst I could do would be to iterate over each item, .get('id'), and return that one.
Take a look at the get method, it may be of some help :)
http://backbonejs.org/#Collection-get
get collection.get(id)
Get a model from a collection, specified by an id, a cid, or by passing in a model.
If your data requires you to use a different kind of key or a set that doesn't mesh well with at(), getByCid() or get(), there is also where(). Something like this might work:
window.lib = new Library;
window.lib.fetch([
success: function(model, response) {
console.log(window.lib.where({'BookID':488, 'Rev':2, 'Status':'Active'});
}
});