CODEWITHSUNDEEP
sqlruby-on-railsrubyactiverecordrails-activerecord
Adam Templeton
Adam Templeton

Reputation: 4617

How can I get Rails 5 to play nicely with a primary key that has a period in it?

I'm working with a database I have no control over, and cannot make alterations to. This database has a table called warehouse_items. Each warehouse item is uniquely identified by a primary key indicating the item id.

Unfortunately, that primary key attribute is named WAREHOUSE_ITEM.ID

(Note the obnoxious period between "item" and "id")

When I try to run a basic query, such as:

WarehouseItem.find('wh3453')

I get an Undefined Table error.

Fortunately, when looking at what Rails is attempting to do, the problem becomes obvious:

: SELECT  "warehouse_items".* FROM "warehouse_items" WHERE "WAREHOUSE_ITEM"."ID" = $1 LIMIT $2

Because of the period in the attribute name, Rails is treating "WAREHOUSE_ITEM.ID" as a table/attribute combination, rather than an attribute name with a period in it.

When I run the following PSQL query by hand, I get exactly what I need:

SELECT  "warehouse_items".* FROM "warehouse_items" WHERE "warehouse_items"."WAREHOUSE_ITEM.ID" = 'wh3453'

Why is Rails screwing this up, and how can I fix it?

EDIT:

Also worth noting: I've tried using self.primary_key to override the primary key to no avail.

I've tried both a string and a symbol, as in:

self.primary_key="WAREHOUSE_ITEM.ID"

and

self.primary_key=:"WAREHOUSE_ITEM.ID"

Neither one has worked...

Upvotes: 3

Views: 72

Answers (1)

Adam Templeton
Adam Templeton

Reputation: 4617

Thanks for all the help, everyone!

A suggestion in the comments to use find_by_sql does work! However, I stumbled onto a different solution that works even better.

First, I aliased the annoying attribute name to something simple: id

alias_attribute :id, :"WAREHOUSE_ITEM.ID"

Notice that it's still a symbol, which is important for the next step.

I then overwrite the primary_key method with a custom function:

  def self.primary_key
    return "id"
  end

Now, when I do WarehouseItem.find('wh3453'), Rails defaults to checking id, which is aliased to the correct symbol and it works as intended!!!

Upvotes: 1

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