wosephjeber

Renaming table in Ecto migration

I recently wanted to rename a model and its postgres table in a Phoenix app. Renaming the table was simple and documented, but the table also had constraints, sequences, and indexes that needed to be updated in order for the Ecto model to be able to rely on default naming conventions. I couldn't find any examples of what this would look like but was eventually able to figure it out. For anyone else in the same situation, hopefully this example helps.

In the example below, I'm renaming the Permission model to Membership. This model belongs to a User and an Account, so it has foreign key constraints that need to be renamed.

defmodule MyApp.Repo.Migrations.RenamePermissionsToMemberships do
  use Ecto.Migration

jdrew1303

Introduction

The computer driven markets for instruments like stocks and exchange traded stock options, have transformed finance and the flow of capital. These markets are enabled by order matching engines (and the infrastructure that supports this software). Before computer trading networks and matching engines, stocks where traded on cavernous exchange floors and transaction costs where high. When electronic trading fully matured, floor traders were a fading anachronism and transaction costs had been reduced to pennies a share in many cases. Electronic trading could not exist without advanced network infrastructure, but without the software matching engines no shares would change hands. The computer trading networks, the matching engine software has also created a concentrated nexus of potential failure. Failures in these systems have increased as the frequency and volume on the electronic networks has increased. The position of order matching engines in the trading infrastructure makes these systems o

tachesimazzoca

Capistrano Custom SCM

Overview

Capistrano 3.7.0 and newer has three SCM plugins (Git/Subversion/Mercurial).

• http://capistranorb.com/documentation/advanced-features/custom-scm/

As the link above shows, it is also possible to provide a custom SCM plugin. The implementations of the default plugins would help you know the nuts and bolts.

mjrode

The Complete Guide to Nested Forms in Phoenix

I recently spent some time dealing with nested forms in Phoenix. Nested forms are great when you want to create multiple database records in a single transaction and associate them with each other. I am new to Phoenix and really struggled to find any resources that helped me with my specific problem. I decided to document what I learned in the process in hopes of helping others that are new to Elixir and Phoenix.

Here is my attempt at a one stop shop to learn everything you will need to know about nested forms. If you would like to view the GitHub repo you can check it out here.

Thanks to Heartbeat and Jose for excellent blog posts on nested forms. Also shoutout to Josh for showing me some examples at Ruby

jvns

A lot of these are outright stolen from Edward O'Campo-Gooding's list of questions. I really like his list.

I'm having some trouble paring this down to a manageable list of questions -- I realistically want to know all of these things before starting to work at a company, but it's a lot to ask all at once. My current game plan is to pick 6 before an interview and ask those.

I'd love comments and suggestions about any of these.

I've found questions like "do you have smart people? Can I learn a lot at your company?" to be basically totally useless -- everybody will say "yeah, definitely!" and it's hard to learn anything from them. So I'm trying to make all of these questions pretty concrete -- if a team doesn't have an issue tracker, they don't have an issue tracker.

I'm also mostly not asking about principles, but the way things are -- not "do you think code review is important?", but "Does all code get reviewed?".

tcnksm

class Foo
  class << self
    def exec
      something
    rescue => ex
      ex.message
    end
    
    def something
      "something"

zhengjia

=Navigating=
    visit('/projects')
    visit(post_comments_path(post))

=Clicking links and buttons=
    click_link('id-of-link')
    click_link('Link Text')
    click_button('Save')
    click('Link Text') # Click either a link or a button
    click('Button Value')