Referring child nodes in allOf if then condition in parent node - json

Question

{
"$schema":"https://json-schema.org/draft/2019-09/schema",
"$id":"PersonalDetails.json",
"type":"object",
"properties":{
"Header":{
"type":"object",
"properties":{
"HeaderName":{
"type":"string"
},
"HeaderValue":{
"type":"string"
}
}
},
"Details":{
"type":"array",
"items":{
"type":"object",
"properties":{
"FName":{
"type":"string"
},
"LName":{
"type":"string"
},
"Address":{
"type":"object",
"properties":{
"FlatNo":{
"type":"string"
},
"Sector":{
"type":"string"
},
"LandMarks":{
"type":"object",
"properties":{
"LandMark1":{
"type":"string"
},
"LandMark2":{
"type":"string"
}
}
}
},
"required":[
"Sector"
]
}
}
}
}
}
}
{
"Header":{
"HeaderName":"DummyName",
"HeaderValue":"DummyName"
},
"Details":[
{
"FName":"Chicago",
"LName":"Laos",
"Address":{
"FlatNo":"Excalibur",
"Sector":"07",
"LandMarks":{
"LandMark1":"USA",
"LandMark2":"UK"
}
}
}
]
}
So the requirement is to insert IF then conditions in Json Schema with following conditions
if LandMark1 = USA and FlatNo = Excalibur
then Sector is required
I am not able to figure out where exactly should i place this condition and its syntax
i tried using $ref in if then conditions in allOf in Details as its parent for both Address and LandMarks
but even that didn't work as it was not able to figure out reference
Any help is highly apprecitiable

Answer 1

You'll need to use the if/then keywords to describe this. The hard part is the if schema.
You need to define an if schema that will validate to true when given an instance where your conditions are met. It can help to develop this schema separately and then add it to your full schema.
{
"type": "object",
"properties": {
"FlatNo": { "const": "Excalibur" },
"LandMarks": {
"type": "object",
"properties": {
"LandMark1": { "const": "USA" }
},
"required": ["LandMark1"]
}
},
"required": ["LandMarks", "FlatNo"]
}
The following instance would pass validation against that schema. It would fail if FlatNo != Excalibur or LandMark1 != USA.
{
"FlatNo":"Excalibur",
"Sector":"07",
"LandMarks":{
"LandMark1":"USA",
"LandMark2":"UK"
}
}
Now it should be trivial to apply if/then to your address schema.
"if": { ... schema from above ... },
"then": { "required": ["Sector"] }