Re: [Artanis] Foreign Key for Migrations

[Nala Ginrut]

Hi Jonathan!
Sorry it's my mistake to neglect this part in the doc.
You don't have to take care of the DB connection management by
yourself. You may just use `art draw model person' to create the named
mapping to the "person" table, and there's an exported relational
mapping object named "$person", you may import (app models person) in
other controller to use it. It's based on FPRM, but the table name has
already been wrapped into the closure:
https://www.gnu.org/software/artanis/manual/manual.html#orgeff2a47

And maybe read its implementation is clearer to you:
https://gitlab.com/NalaGinrut/artanis/blob/master/artanis/mvc/model.scm#L226

The usage should look like this:

($person 'set #:name "nala" #:age 100)

BTW, please don't forget to config your DB in conf/artanis.conf first.

Best regards.


Jonathan Schmeling writes:

> Gotcha. That makes a lot of sense. Thanks a ton for explaining!
>
> Database related, is there a way to query the database from one of the 
> controller -define methods (like (article-define show …) in the online 
> documentation)? Using the function map-table-from-DB causes an error and 
> attaching #:conn #t, like with the get function, also causes an error. Doing 
> something like (:conn rc "SELECT * FROM PEOPLE") seems to work (or, at least, 
> not throw an error) but I'm not sure what gets returned. The doc. says the 
> returned value is described at 
> https://www.gnu.org/software/artanis/manual/manual.html#org8ba121f but that 
> section says "TODO".
> As always, any help is always super appreciated!
>
> Jonathan
>
> On 2/17/19 12:19 PM, Nala Ginrut wrote:
>
>
> Hi Jonathan!
> I'm glad you asked this question.
> The answer is actually written in the fprm.scm code comments that the
> relational mapping in Artanis is not going to provide database level
> foreign keys. The solution is to provide higher-abstract-level table
> operations as a replacement to save users to time to handle by
> themselves.
>
> The pros and cons of foreign keys are discussed a lot in the
> internet. The modern ORM may choose to drop foreign keys and provide
> higher layer for it.
>
>
> Unfortunately, this feature has not been implemented yet because of my time 
> schedule.
>
> Of course, this issue is still open, the original plan is more
> ambitious. I think it's the time to add more features to the relational
> mapping framework.
> Welcome to discuss if you like.
>
> Best regards.
>
> Jonathan Schmeling writes:
>
>
>
> I'm not sure if it's been asked before but I couldn't find any mention
> in the doc. – is it feasible to define foreign keys for the create-table
> function? I want to reference another table's primary keys from a
> particular table, to link them.
>
> Jonathan


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