Hello,
>> [db][get,’people’] // *{name:@string, age:!gt(20)&!lt(33)}
>>
>> We have lost information about the “schema.” This is not good as
>> compile-time write validation is not possible.
>>
>
> So far, I am thinking: yeah, dealing with schema changes can be tricky.
This is not a “schema change” but a greater specification of what the referents
are. Again, a reference is defined by its referent pattern (and instruction
patterns). The referent pattern is a description of the current instances
(referents) while the “schema” is a description of what is legal for all
instances (referents). Without “schema,” I lose compile-time validation.
> I then create a people-key on the db map that maintains a person-reference.
>>
>
> OK. I think by people-key you mean the primary key for the person type,
> i.e. the vertex id. Correct me if I am wrong.
No. db.get(‘people’) is the "people table.” RDBMSs are modeled as a map with
the keys being the table names and the values being *{:} references to maps
(i.e. rows).
> I see this as a type plus a constraint. And... you won't be surprised to
> hear me say this... you express it with a select statement:
>
> youngishPeople := σ_{age <= 20 ∧ age >= 33}(people)
Well, type definitions like this won’t happen at runtime. The VM will just be
able to tell you if the range has been restricted. It won’t create new types.
But yea, referent patterns are (now) a type plus a constraint. Before, they
were just constraints and that is why I lost schema information at runtime.
Take care,
Marko.
http://rredux.com
