JavaScript Object Notation (JSON) is a highly popular format for storing and transferring data, especially in the realm of web development. JSON can sometimes be intimidating for those more familiar with tabular or XML data exchange formats. We’ll demystify JSON with a high-level overview of the format. We’ll then discuss the variety of built-in T-SQL functionality available to store, query, or even generate JSON within your SQL Server databases.

1. Demystifying JSON in SQL
Server
BY KRISTIN FERRIER

2. About Me – Kristin Ferrier
 18+ Years in IT
 Principal Consultant at Ferrier Solutions
 Full stack web developer with specialty and passion for data
 Twitter: @SQLEnergy
 Techlahoma Slack: @EnergyDev
 GitHub: @EnergyDev

3. What we’ll cover
 What is JSON?
 Why use JSON?
 JSON functionality in SQL Server (most of our time will be spent here)
 Built-in functions
 OPENJSON
 FORJSON
 More…

4. What is JSON?
JSON is data

5. What is JSON?
JSON is data
in the form of a JavaScript object
But with stricter rules
Like a string must be enclosed in quotation marks
Above is a practical definition. Officially JSON is “a data exchange format that was created from a subset of the literal object notation in JavaScript”

6. JSON Example
[
{
"QuoteID": 1,
"Franchise": "Star Wars",
"Character": "Yoda",
"QuoteText": "Do. Or do not. There is no try."
},
{
"QuoteID": 2,
"Franchise": "The Librarians",
"Character": "Cassandra",
"QuoteText": "Mathemagics. I like it.."
}
]

7. Why JSON?
 JSON is a very popular data format used for exchanging data in modern web and
mobile applications.
Web / Mobile App Web API
JSON
JSON

8. Why JSON over XML?
 With respect to XML
 JSON is more popular in modern development
 JSON is lighter
 JSON support in SQL Server is simpler

9. Side by Side
JSON XML

10. JSON Functionality in SQL Server
 Available starting with SQL Server 2016 and Azure SQL Database
 Built-in functions
 Validate JSON and Insert/Update/Delete data within JSON
 OPENJSON
 JSON => Tabular
 FORJSON
 Tabular => JSON
 More…
 Indexing, constraints, etc.

11. JSON Built-in Functions
 ISJSON – Validate that text is formatted as JSON
ISJSON(@json)-> bit (0, 1, or null)
 JSON_VALUE – Extract value from JSON text
JSON_VALUE(@json, '$.FranchiseID') -> NVARCHAR(4000)
 JSON_QUERY – Extract JSON fragment from JSON text
JSON_QUERY(@json, '$.Characters') -> NVARCHAR(MAX)
 JSON_MODIFY – Update, delete, or add properties in JSON text
JSON_MODIFY(@json, '$.FranchiseProducer', 'Devlin') -> NVARCHAR(MAX)

12. JSON Built-in Functions
DEMO TIME

13. OPENJSON
 Converts JSON to table data

14. OPENJSON

15. OPENJSON
DEMO TIME

16. FOR JSON
 Tabular data => JSON
 FOR JSON AUTO
 Defaults JSON structure
 Some customization
 Requires FROM clause
 FOR JSON PATH
 Customize overall JSON structure
 Doesn’t require FROM clause

17. FOR JSON

18. FOR JSON
DEMO TIME

19. Additional features
 ISJSON constraints on JSON fields
CONSTRAINT ensure_episodeJson CHECK (ISJSON(EpisodeJson) = 1)
 Indexing
ALTER TABLE dbo.Episode
ADD vDirector AS JSON_VALUE(EpisodeJSON, '$.director')
CREATE INDEX idx_episode_json_director
ON dbo.Episode(vDirector)

20. Q&A and Thank You
Q&A
Catch up with me later
 Twitter @SQLEnergy
 Techlahoma Slack @EnergyDev