JSON-SCHEMA Tutorial

JSON-SCHEMA Tutorial [OSWf4a9514baed04859a4c6c374a7312f10]
ID	OSWf4a9514baed04859a4c6c374a7312f10
UUID	f4a9514b-aed0-4859-a4c6-c374a7312f10
Label	JSON-SCHEMA Tutorial
Machine compatible name	JsonSchemaTutorial

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Statements (incoming)

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Type(s)/Category(s)	Tutorial

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Tutorial
Prerequisites (required)	JSON Tutorial
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Follow-up (recommended)	JSON-LD Tutorial JSON Application Tutorial

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JSON-SCHEMA: Motivation

Problem: If many JSON-Files are created over time by different people / tools, you want them to follow a certain structure

JSON Dataset 1

{
    "c": 1.0
}

JSON Dataset 2

{
    "c": "1.0"
}

They express the same information, but are different / incompatible

JSON-SCHEMA: Validation (1)

A JSON-SCHEMA can describe and validate a JSON-Document

JSON Schema

{
    "type": "object",
    "properties": {
        "c": {
            "type": "number"
        }
    }
}

JSON Dataset 1

{
    "c": 1.0



}

Dataset 1 is valid

JSON-SCHEMA: Validation (2)

A JSON-SCHEMA can describe and validate a JSON-Document

JSON Schema

{
    "type": "object",
    "properties": {
        "c": {
            "type": "number"
        }
    }
}

JSON Dataset 2

{
    "c": "1.0"



}

Dataset 2 is not valid

JSON-SCHEMA: Definition

What is a JSON-SCHEMA?

A JSON document defining the valid structure of another JSON document
The "type" keyword is special. It allows us to specify which values of a JSON object are valid! [1]

JSON-SCHEMA: the "type" Keyword

What is a JSON-SCHEMA?

A JSON document defining the valid structure of another JSON document
The "type" keyword is special. It allows us to specify which values of a JSON object are valid!
json-schema.org defines the following basic types [2]:
- string
- number
- integer
- object
- array
- boolean
- null

JSON-SCHEMA: Typing

How to define a JSON-SCHEMA?

We want to levearge the power of typing and validation
Therefore, our defined key(word):value pairs need to become JSON objects, specifying a type!

{
    "title": "Item",
    "type": "object",
    "properties": {
        "name": {
            "type": "string"
        },
        "count": {
            "type": "integer"
        },
        "pi": {
            "type": "number"
        },
        "validated": {
            "type": "boolean"
        }     
    }
}

JSON-SCHEMA: Reference

How to define a JSON-SCHEMA?

We want to levearge the power of typing and validation
Therefore, our defined key(word):value pairs need to become JSON objects, specifying a type!
JSON (object) properties posses a keyword, which is used for reference

{
    "title": "Item",
    "type": "object",
    "properties": {
        "name": {
            "type": "string"
        },
        "count": {
            "type": "integer"
        },
        "pi": {
            "type": "number"
        },
        "validated": {
            "type": "boolean"
        }     
    }
}

JSON-SCHEMA: Other Keywords (1)

How to define a JSON-SCHEMA?

We want to levearge the power of typing and validation
Therefore, our defined key(word):value pairs need to become JSON objects, specifying a type!
JSON (object) properties posses a keyword, which is used for reference
JSON properties, being objects, can also have a title - e.g., for display purpose

{
    "title": "Item",
    "type": "object",
    "properties": {
        "name": {
            "title": "Name",    
            "type": "string"
        },
        "count": {
            "title": "Count",  
            "type": "integer"
        },
        "pi": {
            "title": "Pi",  
            "type": "number"
        },
        "validated": {
            "title": "Validation status",  
            "type": "boolean"
        }     
    }
}

JSON-SCHEMA: Other Keywords (2)

How to define a JSON-SCHEMA?

We want to levearge the power of typing and validation
Therefore, our defined key(word):value pairs need to become JSON objects, specifying a type!
JSON (object) properties posses a keyword, which is used for reference
JSON properties, being objects, can also have a title - e.g., for display purpose
Usefull other keywords:
- "description" - to give a context

{
    "title": "Item",
    "type": "object",
    "properties": {
        "name": {
            "title": "Name",
            "description": "The name of the item",    
            "type": "string"
        }  
    }
}

JSON-SCHEMA: Other Keywords (3)

How to define a JSON-SCHEMA?

We want to levearge the power of typing and validation
Therefore, our defined key(word):value pairs need to become JSON objects, specifying a type!
JSON (object) properties posses a keyword, which is used for reference
JSON properties, being objects, can also have a title - e.g., for display purpose
Usefull other keywords:
- "description" - to give a context
- "default" - to specify a fall back if no value is entered

{
    "title": "Item",
    "type": "object",
    "properties": {
        "name": {
            "title": "Name",
            "description": "The name of the item",
            "default": "John Doe",    
            "type": "string"
        }  
    }
}