CODEWITHSUNDEEP
ruby-on-railsdatabase
John Dough
John Dough

Reputation: 125

How do I add a column that points to another table in a Rails database?

Let's say I currently have a table titled "Report" and within Report, there are a bunch of strings, integers, timestamps, etc.

Now, I want to somehow be able to see who is currently working on a certain report - all I need are names, but the key is it could be more than one name so just adding a string column to the Report table wouldn't work. Plus, the names would keep changing - at one point, "Steve" and "John" could be working on a report, but once "Steve" stops, I need to be able to get rid of his name from the table.

I have a feeling that the correct way to do this is by:

I think that makes sense logically, but I'm hesitant to implement this without being sure that this is the way to go. Any help/feedback/suggestions would be appreciated!

Edit:

I created a model for my join table and it auto-generated a migration and added an integer "viewer_id" and an integer "report_id" like Vimsha suggested below. However, I can't correctly implement the join tables in my code for some reason - when I want to add to the new Table (report_viewers), I say:

@viewer = ReportViewer.new
@viewer.viewer_id = get_current_user[:id]
@viewer.report_id = this_report.id
@viewer.save

However, when I access the table via 

ReportViewer.where(:report_id => my_report.id).last.viewer_id.name (the viewer table has a string name)

it gives me a nil class. Do you know why?

Upvotes: 0

Views: 71

Answers (2)

anonn023432
anonn023432

Reputation: 3120

What i usually do is use

rails generate migration addviewertoreport

and then just add the relevant commands

Upvotes: 0

usha
usha

Reputation: 29349

Looks like you need a join table report_viewers

report_viewers

-report_id
-viewer_id

When you detect a new viewer, add an entry with report_id and viewer_id. Remove the record if the viewer stops viewing the report.

Upvotes: 3

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