Schema update for relational data

[tjohnson-scottlogic]

Description

Extend the scope of the JSON schema to include validation of the relationships section of the profile (which is described here).

Changes

• Add relationships section to the top of the schema.
• Add relationship definition to bottom of the schema, to add validation of as much of the logic described in the RelationalData page as possible.
• Add reference to the RelationalData page in the UserGuide.
• Test by performing profile validation of the relational example.

Additional notes

Couldn't work out how to do validation of extents.

Issue

Resolves #1708

[Tom-hayden]

Looks good to me!

[ghost]

Main issue here is the 'profile' property in the schema should refer back to the main schema. Otherwise there are 2+ profile schemas to maintain.

[ghost]

Can you 'ref' back to the main schema here? This object should confirm to the profile schema, and can contain relationships itself which isn't represented here?

[tjohnson-scottlogic]

Ah, hadn't realised a relationship could contain another relationship. I can't work out how to refer back to the main schema, but I have added a relationships section at the bottom, which seems to work. Not ideal to have fields, constraints and relationships defined twice though.

[ghost]

Can you do something like this?

...
"profile": {
   "$ref": "#/"
}
...

[tjohnson-scottlogic]

I don't think so. From how I understand it you have to have some initial entries in the schema first, then they can refer to definitions below. I don't think you can effectively go straight to the definitions. I tried the above anyhow but it didn't work for me.

[tjohnson-scottlogic]

As discussed @sl-slaing, our aim is to not change the profile format itself and to fix this in the schema. We also don't want to have fields, constraints and relationships defined in two places. The Recursion section of the JSON Schema Reference should help, just can't figure it out at the moment.