ReQL: pluses and minuses of pipeline-style queries

[Rikki Cattermole via Digitalmars-d]

On 26/04/2015 1:59 a.m., w0rp wrote:
> On Saturday, 25 April 2015 at 05:16:21 UTC, Andrei Alexandrescu wrote:
>> Found this on reddit a few days ago:
>> http://rob.conery.io/2015/04/17/rethinkdb-2-0-is-amazing/
>>
>> A good discussion of the pros and cons of pipeline-style queries (the
>> ReQL query language reminiscent of D's algorithms/ranges) vs. classic
>> SQL.
>>
>>
>> Andrei
>
> One thing *kind of* related that I have really enjoyed is Django's
> querysets for building SQL queries. In Django, a QuerySet has methods
> query yields new QuerySet objects, so you can build a set of parameters
> and SQL is eventually generated and then executed to yield the results.
>
> andrei_queryset = (
>      People.objects
>      .filter(first_name="Andrei", last_name__startswith="Al")
>      .order_by("-affinity_for_template_metaprogramming")
>      .select_related("organisation")
>      [0:5]
> )
>
> The above would, when evaluated, generate something like the following
> in order to build the objects with.
>
> SELECT p.*, o.* FROM people AS p
> INNER JOIN organisation AS o
> ON o.id = p.organisation_id
> WHERE first_name = "Andrei"
> AND last_name LIKE "Al%"
> ORDER BY affinity_for_template_metaprogramming DESC
> LIMIT 5;
>
> I've been trying to think of a way to create something similar in D,
> maybe for something like HiberateD.

I'm personally moving towards a DSL.

unittest {
	auto myQuery = """
using webdev.base.orm.query.parser.defs # allow for D class name instead 
of table name
; # end of \"sentence\"

from MyModel
where key == $0
as simple
# as index # but only one can be defined, two in total internal
; # end of \"sentence\"

from MyModel
where value contains $0
as complex
# as index # but only one can be defined, two in total internal
; # end of \"sentence\"

""".query;

	MyModel[] gotValues = myQuery.simple("test");
	gotValues = myQuery.perform("complex", "another");
}

Pros:
- Runtime reloadability
- Runtime composability
- More flexible
Cons:
- It's a string