Introduction to JSON

In this article, we will discuss the first two points from the following. In upcoming articles, I will discuss how to create a JSON file from a database table.
  • Introduction to JSON
  • JSON syntax
  • Parsing and Generating JSON files
  • JSON data storage application
So let us start with the introduction part.

What is JSON?

JSON (Javascript Object Notation) is a lightweight data-interchange format.
Why use it
  • Same syntax as JavaScript objects.
  • Easy for humans to read and write.
  • Language independent.
  • It can be used to store application data.

How can we create /read JSON file?

We can create/read a JSON file by using:
  • JavaScriptSerializer (inbuilt in dotnet framework).
  • JSON.NET third party tool (download from Nuget Package Manager).
So let us look at JSON:
{ } culry braces represent object
key – value pair
JSON Syntax
So what exactly makes up a JSON file:
  • Values
  • Objects
  • Arrays
  • Putting it all together
JSON Values can be
  • Strings ( in double quotes)
  • Numbers (integer or floating point)
  • Boolean ( true or false )
  • Objects ( in curly brackets)
  • Array( in square brackets)
  • Null
JSON Object
  • Name/value pairs using colons
  • Enclose by curly braces
  • Pairs separated by commas
Example
  1. {
  2. name: values,
  3. name2: values2
  4. }
So here is a very simple example curly braces representing json object, name values pair separated by comma:
  1. {
  2. "Name" :"Ravi",
  3. "City": "Varanasi",
  4. }
More complex example
  1. {
  2. "countryId": 1,
  3. "countryName" : "India",
  4. "state" : ["uttar pradesh","Mumbai","Bangalore"]
  5. }
Again we have curly braces representing object. This time we have three name-value pairs: countryId is just integer, countryName is string and state is arrays shown by bracket,

JSON Arrays

  • Values enclosed by brackets
  • Separated by commas [item,item,item,item]
Example
["uttar pradesh","Mumbai","Bangalore"]
Indicated by bracket we have JSON arrays and in this example its an array of three string and each string separated by commas:
[1,2,3,4] its array of number
Complex array
  1. [
  2. {
  3. "AlbumId": 3,
  4. "GenreId": 1,
  5. "ArtistId": 4,
  6. },
  7. {
  8. "AlbumId": 5,
  9. "GenreId": 1,
  10. "ArtistId": 77,
  11. }]
So array can be a collection of anything including object and these objects have three name-value pairs.
Putting it all together
  • JSON values can also be objects or arrays
  • JSON objects and arrays can be nested
Points of Interest
  • In this article, I have touched the very basics of JSON.
  • JSON is very useful in client-server communication where network bandwidth is very limited.