How to validate object values in jsonschema? - jsonschema

Question

Suppose I have a json like this:
{"1": {"first_name": "a", "last_name": "b"},
"2": {"first_name": "c", "last_name": "d"}}
As you can see, values have such schema:
{"type": "object",
"properties": {
"first_name": {"type": "string"},
"last_name": {"type": "string"}
},
"additionalProperties": false,
"required": ["first_name", "last_name"]}
I want to know how can I define a schema which can validate the above json?

Answer 1

The additionalProperties takes a JSON Schema as it's value. (Yes, a boolean is a valid JSON Schema!)
Let's recap what the additionalProperties keyword does...
The behavior of this keyword depends on the presence and annotation
results of "properties" and "patternProperties" within the same schema
object. Validation with "additionalProperties" applies only to the
child values of instance names that do not appear in the annotation
results of either "properties" or "patternProperties".
For all such properties, validation succeeds if the child instance
validates against the "additionalProperties" schema.
https://json-schema.org/draft/2020-12/json-schema-core.html#additionalProperties
In simplest terms, if you don't use properties or patternProperties within the same schema object, the value schema of additionalProperties applies to ALL values of the applicable object in your instance.
As such, you only need to nest your existing schema as follows.
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"additionalProperties": YOUR SCHEMA
}