Databases
StackOverflow2013
Postsdbo
POCan't convert hash to integer - Trying to select random record
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POCan't convert hash to integer - Trying to select random record
    primarykey
    data
    text
    <p>I'm trying to select a random record, but the only working method seems like a horrible performance liability.</p> <p>First attempt, using RANDOM function from Postgres - throws "Can't convert Hash into Integer"</p> <pre><code> assigned_specialist = User.specialists.legal_for(coach_section).experienced_in(critique.discipline_id).first(:order =&gt; "RANDOM()") return assigned_specialist.id </code></pre> <p>Second attempt, using <a href="https://stackoverflow.com/questions/2752231/random-record-in-activerecord">offset method discussed here.</a> Also causes "Can't convert Hash into Integer"</p> <pre><code> legal_specialists = User.specialists.legal_for(coach_section).experienced_in(critique.discipline_id) offset = rand(legal_specialists.count) assigned_specialist = legal_specialists.first(:offset =&gt; offset) return assigned_specialist.id </code></pre> <p>Final attempt, using array sample method, which works but seems bad.</p> <pre><code> legal_specialists = User.specialists.legal_for(coach_section).experienced_in(critique.discipline_id) assigned_specialist = legal_specialists.sample return assigned_specialist.id </code></pre> <p>To be fair, there will only be about 20 specialists in the system, so the array sample method might never cause any issues, but I'd still like to understand what's going on here.</p> <p><strong>Edit</strong>: Here are the scopes I defined: </p> <pre><code>scope :specialists, where(:role_id =&gt; 2) scope :legal_for, lambda { |coach_section| where("section_id != ?", coach_section) } scope :experienced_in, lambda { |discipline_id| discipline = Discipline.find(discipline_id) discipline.users } </code></pre>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USCommunity
    1. USChris Fletcher
    plurals
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload