ORM for Javascript/JSON - javascript

I am working on a web application that gets JSON data from the server (Ruby/Rails) into the client using jQuery/ajax and then renders it to the browser using jQuery to populate the DOM. To simplify access to my data on the client side, I would like to use an object-relational mapper similar to ActiveRecord, but which starts with JSON data instead of data directly from a SQL data source.
Are there any such ORMs in Javascript that convert a JSON data set (itself derived from a set of SQL queries on the server side) to a set of ActiveRecord-like objects?

I may be missing something here, but JSON (JavaScript Object Notation) is already a Javascript object in and of itself.
If the data you are getting from the server doesn't map well to a usable Javascript object, I would argue that it's the server side that needs to change to return a more useful serialized object rather than a simple recordset.

ExtJS has a very nice JsonStore class

There is CouchDB which is a DB written in Erlang that uses HTTP as the transport. This eliminates the need for middle-ware and permits you to navigate the DB directly with AJAX calls. I can't speak good or bad about it. I haven't heard much about it in months and it seems as if the hype train departed a few years ago.
You can't have an ORM to a remote DB in Javascript.. An, ORM requires transcendental knowledge of the DB schema, and sending that out with an API just isn't that pragmatic as of yet.
For persistent local storage, there is the now deprecated Google Gears and the HTML5 Clientside DB.

Yes there is JSON ODM. Exactly what you are looking for. If you need a method that is not supported yet post an issue and I'll try my best to support it as soon as possible.
If you like it please give it a star!

Related

Call a stored procedure via javascript on the client side?

Is it possible to call a stored procedure within javascript on the client side?
I know how to do on the server side, but I am interesting in doing on the client side.
Basically it boils down to directly contacting a SQL server from within the client. Is that possible?
tldr; No, it is not possible to connect to SQL Server 'directly' from browser-JavaScript1.
JavaScript can "speak" HTTP and WebSockets, but SQL Server "speaks" TDS. To communicate there needs to be a common medium/protocol that both the client and server use.
While there are WebSocket proxies that technically make this possible it still requires a separate proxy service (and you'd still have to write/find a JavaScript TDS driver). I don't recommend eliminating the controlled access layer.
Likewise, an HTTP proxy where raw SQL commands are sent to/from the client could be used. I wouldn't advise this either, but some do exist.
External code/libraries (eg. ActiveX, Java) could establish the SQL connection and proxy through to the JavaScript client.
In all of these cases there is an intermediate helper and browser-JavaScript never connects 'directly'.
1 JavaScript is a language and this answer focuses on a browser implementation with browser-supported libraries/functions. One could argue that using node modules would still 'be JavaScript', and they would be correct .. in a different environment.
You cannot establish a direct connection to a database from a client's web browser. What you will need to do is create a server side application to expose an API for getting the data over HTTP.
Take a look at Microsoft's ASP.NET Web API
Sort of
You could create an endpoint that is a wrapper for stored procedure(s) that takes the procedure name as a parameter, as well as the parameters for the procedure.
Once you have such a mechanism in place, you can create endpoints that expose procedures automagically.
http://yourserver/services/yourprocname?prm1=val,prm2=val,etc
If you feel really ambitious you can try out SQL 2016 and return JSON directly from those procedures. Then you can nest data using subqueries and return the JSON in a single payload. No serialization, no objects, just read the data and return it.
< 2016 you could put the results into a Dictionary and use NewtonSoft to serialize it. Assuming you are returning flat data you'd be good to go. Just use a reader and get the meta data from the column names for the key, and the value as object. NewtonSoft will convert that into JSON for you.
If you are returning hierarchical you could (by convention) create a series of runners that take the reader, and pump it into a Dictionary where object is another Dictionary Again the Newtonsoft stuff will help you out with the serialization.
Hope this helps, we are using this approach with 2016 and it is very nice to be able to create a stored procedure and call it without any middle tier code, deployment, etc. It just works.
Hope this helps.
Yes, you can connect to SQL Server from Client side directly by using the WebAssembly. You can write your function that calls the SQL Server in C or C++ first. Compile it to .Wasm by Emscripten compiler. Then you can call the C or C++ code by using JavaScript. In future, you should be able to do that with C# but Microsoft just started work on that.
I am writing a post about it, and I will share it when it's ready.
Now just because you can do it, doesn't mean you should because of security issues. But I am not here to give a lecture about what you should or should not do.

JavaScript framework and JSON Schemas

I came across this question and was quite baffled. I could not understand the underlying thoughts behind this. I have done some API intergation using AngularJS usng $http and $resource when its RESTFul, but these two questions was something like a puzzle. I want to understand this in detail.
Does the JavaScript framework you choose support a model abstraction
with REST integration? If so, what schema does it expect the JSON
replies to use?
Can anyone explain me the two questions.
Some libraries expect your REST API to return specifically structured result. (HAL, JSONP, HATEOAS, ...)
By default, $resource works best with HAL, but it can easily be extended to support other types of return formats (https://github.com/jmarquis/angular-hateoas)
Maybe the question is asking about something like jQuery.map() which allows you to convert the JSON object from the server to your own internal object (abstracted model).
If you use the object from the server throughout your code, and that object's schema changes (e.g. email string changes to emails array), you may have to change your code in many places. But if you've mapped the server data to a local object, you may only need to change the mapping (e.g. set internal email to first value from server emails).

How to assert/unit-test servers JSON response?

My current project uses JSON as data interchange format. Both Front-end and Back-end team agree upon a JSON structure before start integrating a service. At times due to un-notified changes in JSON structure by back-end team; it breaks the front-end code.
Is there any external library that we could use to compare a mock JSON (fixture) with servers JSON response. Basically it should assert the whole JSON object and should throw an error if there is any violation in servers JSON format.
Additional info: App is built on JQuery consuming REST JSON services.
I would recommend a schema for your JSON objects.
I use Kwalify but you can also use Rx if you like that syntax better.
I've been using QUnit: http://docs.jquery.com/QUnit recently for a lot of my JS code.
asyncTest http://docs.jquery.com/QUnit/asyncTest could be used pretty effectively to test JSON Structure.
Example:
asyncTest("Test JSON API 1", 1, function() {
$.getJSON("http://test.com/json", function(data) {
equals(data.expected, "what you expected", "Found it");
});
});
Looks like you're trying to solve a problem from other end. Why should you as a front-end developer bother with testing back-end developer's work?
A JSON that is generated on server is better to test on server using standard approach, i.e. functional tests in xUnit. You could also look at acceptance test frameworks like FITnesse if you want to have tests and documentation wiki all in one.
If even after introducing testing on server you'll get invalid JSON it is a problem in human communication, not in tests.
Since there is no answer I'll put my two cents in.
If the problem is that you are dealing with shifting requirements from the back-end then what you need to do is isolate yourself from those changes. Put an abstraction between the front-end and back-end.
Maybe you can call this abstraction the JSON Data Format Interchange.
So when GUI unit-testing (hopefully you are TDDing your Web GUI) you will have a mock for the JSON DIF. SO when the time to integrate the back-end with the front-end*, any software changes will be done in the abstraction layer implementation. And of course you already have tests for those based upon the agreed upon JSON structure.
OBTW, I think that the server-side team should have responsibility for specifying the protocol to be used against the server.
*Why does this remind of the joke my butt and your face could be twins.
https://github.com/skyscreamer/JSONassert may be helpful in eliminating false positives, so that if the order of fields returned by server changes, but overall response is the same, it doesn't trigger a failure.

Javascript Fastest Local Database

What would be the best format for storing a relatively large amount of data (essentially a big hashmap) for quick retrieval using javascript? It would need to support Unicode as well.
XML, JSON?
Gigantic javascript objects are generally a sign that you're trying to do something you really shouldn't be doing. XML is even worse, it has to be parsed to form meaningful data.
In this case an AJAX query to RESTful interface to a proper database backend would probably serve you well.
Javascript object access (particularly for any query beyond accessing a single item by its hash) is very slow compared to even a basic database.
There is a nice research of the people at flickr about this topic. They ended up by using csv over xml and json.
JSON definitely beats XML for performance reasons.
But a query against DB on the backend would probably be the only feasible solution once a certain scale is reached, since local resources can not possibly match data retrieval from large store compared to DB.

Is JSON used only for JavaScript?

I am storing a JSON string in the database that represents a set of properties. In the code behind, I export it and use it for some custom logic. Essentially, I am using it only as a storage mechanism. I understand XML is better suited for this, but I read that JSON is faster and preferred.
Is it a good practice to use JSON if the intention is not to use the string on the client side?
JSON is a perfectly valid way of storing structured data and simpler and more concise than XML. I don't think it is a "bad practice" to use it for the same reason someone would use XML as long as you understand and are OK with its limitations.
Whether it's good practice I can't say, but it strikes me as odd. Having XML fields in your SQL database are at least queryable (SQL Server 2000 or later, MySQL and others) but more often than not is a last resort for metadata.
JSON is usually the carrier between JavaScript and your back end, not the storage itself unless you have a JSON back end document orientated database such as CouchDB or SOLR as JSON lends itself perfectly for storing documents.
Not to say I don't agree with using JSON as a simple (that is, not serializing references) data serializer over XML, but I won't go into a JSON vs XML rant just for the sake of it :).
If you're not using JSON for its portability between 2 languages, and you're positive you will never query the data from SQL you will be better off with the default serialization from .NET.
You're not the only one using JSON for data storage. CouchDB is a document-oriented database which uses JSON for storing information. They initially stored that info as XML, then switched to JSON. Query-ing is done via good old HTTP.
By the way, CouchDB received some attention lately and is backed by IBM and the Apache Software Foundation. It is written in Erlang and promises a lot (IMHO).
Yeah I think JSON is great. It's an open standard and can be used by any programming language. Most programming languages have libraries to parse and encode JSON as well.
JSON is just a markup language like XML, and due to its more restrictive specification is is smaller in size and faster to generate and parse. So from that aspect it's perfectly acceptable to use in the database if you need ad-hoc structured markup (and you're absolutely sure that using tables isn't possible and/or the best solution).
However, you don't say what database you're using. If it is SQL Server 2005 or later then the database itself has extensive capabilities when dealing with XML, including an XML data type, XQuery support, and the ability to optimise XQuery expressions as part of an execution plan. So if this is the case I'd be much more inclined to use XML and take advantage of the database's facilities.
Just remember that JSON has all of the same problems that XML has as a back-end data store; namely, it in no way replaces a relational database or even a fixed-size binary format. If you have millions of rows and need random access, you will run into all the same fundamental performance issues with JSON that you would with XML. I doubt you're intending to use it for this kind of data store scenario, but you never know... stranger things have been tried :)
JSON is shorter, so it will use less space in your database. I'd probably use it instead of XML or writing my own format.
On the other hand, searching for matches will suck - you're going to have to use "where json like '% somevalue %'" which will be painfully slow. This is the same limitation with any other text storage strategy (xml included).
You shouldn't use either JSON or XML for storing data in a relational database. JSON and XML are serialization formats which are useful for storing data in files or sending over the wire.
If you want to store a set of properties, just create a table for it, with each row beeing a property. That way you can query the data using ordinary SQL.

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