JSON stands for JavaScript Object Notation
Composer Cheat Sheet for developers Composer is the dependency manager for PHP and you are on a one-page-only documentation for this tool. Official documentation is on the official website, this page just brings you the essential. JSON Schema Cheatsheet September 14 2012 3:59am JSON schema is the modern equivalent to XSchema/DDML or the good old ancient DTDs. It provides a lightweight, self-describing and abstract protocol for describing and validating data formats and models.
JSON is a lightweight format for storing and transporting data
JSON is often used when data is sent from a server to a web page
JSON is 'self-describing' and easy to understand
JSON Example
This example defines an employees object: an array of 3 employee records (objects):
'employees':[
{'firstName':'John', 'lastName':'Doe'},
{'firstName':'Anna', 'lastName':'Smith'},
{'firstName':'Peter', 'lastName':'Jones'}
]
}
JSON Syntax Rules
- Data is in name/value pairs
- Data is separated by commas
- Curly braces hold objects
- Square brackets hold arrays
JavaScript Object Notation
The JSON format is syntactically identical to the code for creating JavaScript objects.
Because of this similarity, a JavaScript program can easily convert JSON data into native JavaScript objects.
The JSON syntax is derived from JavaScript object notation syntax, but the JSON format is text only. Code for reading and generating JSON data can be written in any programming language.
JSON Data - A Name and a Value
JSON data is written as name/value pairs, just like JavaScript object properties.
A name/value pair consists of a field name (in double quotes), followed by a colon, followed by a value:
JSON names require double quotes. JavaScript names do not.
JSON Objects
JSON objects are written inside curly braces.
Just like in JavaScript, objects can contain multiple name/value pairs:
JSON Arrays
JSON arrays are written inside square brackets.
Just like in JavaScript, an array can contain objects:
{'firstName':'John', 'lastName':'Doe'},
{'firstName':'Anna', 'lastName':'Smith'},
{'firstName':'Peter', 'lastName':'Jones'}
]
In the example above, the object 'employees' is an array. It contains three objects.
Each object is a record of a person (with a first name and a last name).
Converting a JSON Text to a JavaScript Object
A common use of JSON is to read data from a web server, and display the data in a web page.
For simplicity, this can be demonstrated using a string as input.
First, create a JavaScript string containing JSON syntax:
'{ 'firstName':'John' , 'lastName':'Doe' },' +
'{ 'firstName':'Anna' , 'lastName':'Smith' },' +
'{ 'firstName':'Peter' , 'lastName':'Jones' } ]}';
Then, use the JavaScript built-in function JSON.parse() to convert the string into a JavaScript object:
Finally, use the new JavaScript object in your page:
Example
<script>
document.getElementById('demo').innerHTML =
obj.employees[1].firstName + ' ' + obj.employees[1].lastName;
</script>
Full JSON Tutorial
This has been a short description of JSON.
For a full JSON tutorial go to W3Schools JSON Tutorial.
This post is a reference of my examples for processing JSON data in SQL Server. For more detailed explanations of these functions, please see my post series on JSON in SQL Server 2016:
Additionally, the complete reference for SQL JSON handling can be found at MSDN: https://msdn.microsoft.com/en-us/library/dn921897.aspx
Parsing JSON
Getting string JSON data into a SQL readable form.
ISJSON()
Checks to see if the input string is valid JSON.
JSON_VALUE()
Extracts a specific scalar string value from a JSON string using JSON path expressions.
Strict vs. Lax mode
If the JSON path cannot be found, determines if the function should return a NULL or an error message.
JSON_QUERY()
Returns a JSON fragment for the specified JSON path.
This is useful to help filter an array and then extract values with JSON_VALUE():
OPEN_JSON()
Returns a SQL result set for the specified JSON path. The result set includes columns identifying the datatypes of the parsed data.
Creating JSON
Creating JSON data from either strings or result sets.
FOR JSON AUTO
Automatically creates a JSON string from a SELECT statement. Quick and dirty.
FOR JSON PATH
Formats a SQL query into a JSON string, allowing the user to define structure and formatting.
Modifying JSON
Updating, adding to, and deleting from JSON data.
JSON_MODIFY()
Allows the user to update properties and values, add properties and values, and delete properties and values (the delete is unintuitive, see below).
Modify:
Add:
Delete property:
Json Cheat Sheet Pdf
Delete from array (this is not intuitive, see my Microsoft Connect item to fix this: https://connect.microsoft.com/SQLServer/feedback/details/3120404/sql-modify-json-null-delete-is-not-consistent-between-properties-and-arrays )
SQL JSON Performance Tuning
Json Schema From Json
SQL JSON functions are already fast. Adding computed columns and indexes makes them extremely fast.
Computed Column JSON Indexes
JSON indexes are simply regular indexes on computed columns.
Anydata cdma usb modem (pid 6502) driver download for windows 10. Add a computed column:
Add an index to our computed column:
Json Schema Cheat Sheet Pdf
Performance test: