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.
Related
Here's the two scenarios.
We are using a manually built xml soap request with xmlhttprequest, sending it to a wcf soap service, getting back the response and using xPath to parse the data and fill out a drop down list.
We are sending a json request to a rest wcf service and getting a json response back and assigning the values to a drop down list
Which scenario is faster? My sense tells me #2 but I could be wrong.
Json will be faster, since Json is essentially Javascript. But that shouldn't be the main motivation. Parsing the data, will assumingly be only a small part of your application anyway.
On the other hand, browsers are also well trained to parse XML.
The main difference is that XML, and therefor SOAP, is larger to send to the client, so the transfer may be a bigger slowdown than the parsing.
Anyway, if you want to know, you should just test and profile instead of guessing or asking.
Option two would generally be faster than option one, as JSON is a much simpler format than XML.
However, if you really need the parsing to be fast, you shouldn't use either, you should use a custom format that is really fast to parse using simple string operations. For example a comma separated string that could be parsed with a split(',').
After profiling in my scenario, I found out that JSON is actually much faster as far as processing time within the browser
I'm creating a sophisticated JavaScript library for working with my company's server side framework.
The server side framework encodes its data to a simple XML format. There's no fancy namespacing or anything like that.
Ideally I'd like to parse all of the data in the browser as JSON. However, if I do this I need to rewrite some of the server side code to also spit out JSON. This is a pain because we have public APIs that I can't easily change.
What I'm really concerned about here is performance in the browser of parsing JSON versus XML. Is there really a big difference to be concerned about? Or should I exclusively go for JSON? Does anyone have any experience or benchmarks in the performance difference between the two?
I realize that most modern web developers would probably opt for JSON and I can see why. However, I really am just interested in performance. If there's a proven massive difference then I'm prepared to spend the extra effort in generating JSON server side for the client.
JSON should be faster since it's JS Object Notation, which means it can be recognized natively by JavaScript. In PHP on the GET side of things, I will often do something like this:
<script type="text/javascript">
var data = <?php json_encode($data)?>;
</script>
For more information on this, see here:
Why is Everyone Choosing JSON Over XML for jQuery?
Also...what "extra effort" do you really have to put into "generating" JSON? Surely you can't be saying that you'll be manually building the JSON string? Almost every modern server-side language has libraries that convert native variables into JSON strings. For example, PHP's core json_encode function converts an associative array like this:
$data = array('test'=>'val', 'foo'=>'bar');
into
{"test": "val", "foo": "bar"}
Which is simply a JavaScript object (since there are no associative arrays (strictly speaking) in JS).
Firstly, I'd like to say thanks to everyone who's answered my question. I REALLY appreciate all of your responses.
In regards to this question, I've conducted some further research by running some benchmarks. The parsing happens in the browser. IE 8 is the only browser that doesn't have a native JSON parser. The XML is the same data as the JSON version.
Chrome (version 8.0.552.224), JSON: 92ms, XML: 90ms
Firefox (version 3.6.13), JSON: 65ms, XML: 129ms
IE (version 8.0.6001.18702), JSON: 172ms, XML: 125ms
Interestingly, Chrome seems to have almost the same speed. Please note, this is parsing a lot of data. With little snippets of data, this isn't probably such a big deal.
Benchmarks have been done. Here's one. The difference in some of the earlier browsers appeared to be an entire order of magnitude (on the order of 10s of milliseconds instead of 100s of ms), but not massive. Part of this is in server response time - XML is bulkier as a data format. Part of it is parsing time - JSON lets you send JavaScript objects, while XML requires parsing a document.
You could consider adding to your public API a method to return JSON instead of modifying existing functions if it becomes and issue, unless you don't want to expose the JSON.
See also the SO question When to prefer JSON over XML?
Performance isn't really a consideration, assuming that you're not talking about gigabytes of XML. Yes, it will take longer (XML is more verbose), but it's not going to be something that the user will notice.
The real issue, in my opinion, is support for XML within JavaScript. E4X is nice, but it isn't supported by Microsoft. So you'll need to use a third-party library (such as JQuery) to parse the XML.
If possible, it would make sense to just measure it. By 'if possible' I mean that tooling for javascript (esp. for performance analysis) may not be quite as good as for stand-alone programming languages.
Why measure? Because speculation based solely on properties of data formats is not very useful for performance analysis -- developers' intuitions are notoriously poor at predicting performance. In this case it just means that it all comes down to maturity of respective XML and JSON parser (and generators) in use. XML has the benefit of having been around longer; JSON is bit simpler to process. This based on having actually written libraries for processing both. In the end, if all things are equal (maturity and performance optimization of libraries), JSON can indeed be bit faster to process. But both can be very fast; or very slow with bad implementations.
However: I suspect that you should not worry all that much about performance, like many have already suggested. Both xml and json can be parsed efficiently, and with modern browsers, probably are.
Chances are that if you have performance problems it is not with reading or writing of data but something else; and first step would be actually figuring out what the actual problem is.
since JSON is native in and designed FOR Javascript, it's going to out-perform XML parsing all day long. you didn't mention your server-side language, in PHP there is the json_encode/json_decode functionality built into the PHP core...
the difference in performace will be so tiny, you wouldn't even notice it (and: you shouldn't think about performance problems until you have performance problems - there are a lot of more important points to care for - maintainable, readable and documented code...).
but, to answer ayou question: JSON will be faster to parse (because it's simple javascript object notation).
In this situation, I'd say stick with the XML. All major browsers have a DOM parsing interface that will parse well-formed XML. This link shows a way to use the DOMParser interface in Webkit/Opera/Firefox, as well as the ActiveX DOM Object in IE: https://sites.google.com/a/van-steenbeek.net/archive/explorer_domparser_parsefromstring
It also depends on how your JSON is structured. Tree-like structures tend to parse more efficiently than a list of objects. This is where one's fundamental understanding of data structures will be handy. I would not be surprised if you parse a list-like structure in JSON that might look like this:
{
{
"name": "New York",
"country":"USA",
"lon": -73.948753,
"lat": 40.712784
},
{
"name": "Chicago",
"country":"USA",
"lon": -23.948753,
"lat": 20.712784
},
{
"name": "London",
"country":"UK",
"lon": -13.948753,
"lat": 10.712784
}
}
and then compare it to a tree like structure in XML that might look like this:
<cities>
<country name="USA">
<city name="New York">
<long>-73.948753</long>
<lat>40.712784</lat>
</city>
<city name="Chicago">
<long>-23.948753</long>
<lat>20.712784</lat>
</city>
</country>
<country name="UK">
<city name="London">
<long>-13.948753</long>
<lat>10.712784</lat>
</city>
</country>
</cities>
The XML structure may yield a faster time than that of JSON since if I loop through the node of UK to find London, I don't have to loop through the rest of the countries to find my city. In the JSON example, I just might if London is near the bottom of the list. But, what we have here is a difference in structure. I would be surprised to find that XML is faster in either case or in a case where the structures are exactly the same.
Here is an experiment I did using Python - I know the question is looking at this strictly from a JavaScript perspective, but you might find it useful. The results show that JSON is faster than XML. However, the point is: how you structure is going to have an effect on how efficiently you are able to retrieve it.
Another reason to stick with XML is, that if you switch to JSON, you modify the "maintenance contract". XML is more typed than JSON is, in the sense that it works more naturally with typed languages (i.e. NOT javascript).
If you change to JSON, some future maintainer of the code base might introduce a JSON array at some point which has mixed type content (e.g. [ "Hello", 42, false ]), which will present a problem to any code written in a typed language.
Yes, you could do that as well in XML but it requires extra effort, while in JSON it can just slip in.
And while it does not seem like a big deal at first glance, it actually is as it forces the code in the typed language to stick with a JSON tree instead of deserializing to a native type.
best example i have found about these two is :
http://www.utilities-online.info/xmltojson/#.VVGOlfCYK7M
that means JSON is more human readable and understandable than XML.
I'm coding a website that involves storing very simple data, just a very long list of names with no additional data, on the server. As this data is so simple, I don't really want to use MySQL (it would be a bit too clunky) so I'm asking what's the best way to store very simple data on the server.
I definitely would favour speed over anything else, and easy access to the data via javascript and AJAX would be very good too as the rest of the site is coded in javascript/jQuery. I don't really care if the data can be viewed freely (as it will be available anyway), as long as it can't be changed by unauthorised users.
There are a lot of things to think about with this.
Is the information the same for all users with just a single set that applies to all users out there? Or is there a separate set of data for each user?
How is the data going to be served to the client, my guess here is that you would be having a web service or otherwise that might return a JSON.
From a security standpoint, do you want someone to be able to just "grab" the data and run?
Personally I find that a database if often a better choice, but otherwise i would use an XML file. Keep in mind though that you have to be careful with loading/reading of XML files to serve web requests to prevent any potential file locking issues.
Use an XML file that is web-accessible. Then you can query the XML file from the browser if need be, and still parse/write it in PHP. You'll want to use the flock function in PHP to make sure that two instances of a page don't try to write to the file at the same time.
Write it to a file and save the data as a serialized object. This way when you read in the data it's instantly accessible as the variable type you need (array, obj, etc). This will be faster than XML parsing.
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.
Mostly I have just used XML files to store config info and to provide elementary data persistence. Now I am building a website where I need to store some XML type data. However I am already using JSON extensively throughout the whole thing. Is it bad to store JSON directly instead of XML, or should I store the XML and introduce an XML parser.
Not bad at all. Although there are more XML editors, so if you're going to need to manually edit the files, XML may be better.
Differences between using XML and JSON are:
A lot easier to find an editor supporting nice way to edit XML. I'm aware of no editors that do this for JSON, but there might be some, I hope :)
Extreme portability/interoperability - not everything can read JSON natively whereas pretty much any language/framework these days has XML libraries.
JSON takes up less space
JSON may be faster to process, ESPECIALLY in a JavaScript app where it's native data.
JSON is more human readable for programmers (this is subjective but everyone I know agrees so).
Now, please notice the common thread: any of the benefits of using pure XML listed above are 100% lost immediately as soon as you store JSON as XML payload.
Therefore, the gudelines are as follows:
If wide interoperability is an issue and you talk to something that can't read JSON (like a DB that can read XML natively), use XML.
Otherwise, I'd recommend using JSON
NEVER EVER use JSON as XML payload unless you must use XML as a transport container due to existing protocol needs AND the cost of encoding and decoding JSON to/from XML is somehow prohibitively high as compared to network/storage lossage due to double encoding (I have a major trouble imagining a plausible scenario like this, but who knows...)
UPDATED: Removed Unicode bullets as per info in comments
It's just data, like XML. There's nothing about it that would preclude saving it to disk.
Define "bad". They're both just plain-text formats. Knock yourself out.
If your storing the data as a cache (meaning it was in one format and you had to process it programatically to "make" it JSON. Then I say no problem. As long as the consumer of your JSON reads native JSON then it's standard practice to save cache data to disk or memory.
However if you're storing a configuration file in JSON which needs human interaction to "process" then I may reconsider. Using JSON for simple Key:Value pairs is cool, but anything beyond that, the format may be too compact (meaning nested { and [ brackets can be hard to decipher).
one potential issue with JSON, when there is deep nesting, is readability,
you may actually see ]]]}], making debugging difficult