Rails: How to list database tables/objects using the Rails console?

Question

I was wondering if you could list/examine what databases/objects are available to you in the Rails console. I know you can see them using other tools, I am just curious. Thanks.

Yes, that drops you into mysql (or whatever). For some stranger reason I want to list columns/tables etc from regular console. I am thinking that it might require custom made ruby methods to do such a thing. — rtfminc, Jan 20 '10 at 02:19

score 401 · Accepted Answer · edited Aug 13 '19 at 19:39

401

You are probably seeking:

ActiveRecord::Base.connection.tables

and

ActiveRecord::Base.connection.columns('projects').map(&:name)

You should probably wrap them in shorter syntax inside your .irbrc.

edited Aug 13 '19 at 19:39

Jason Swett

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answered Jan 20 '10 at 02:29

cwninja

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Thanks, the first one works like I want. But the second one doesn't - hunted for something similar but no luck. – rtfminc Jan 20 '10 at 08:36
12

ActiveRecord::Base.connection.columns("foos") should also work, but it returns column objects, .map{|c| [c.name, c.type] } on the end fixes that. – cwninja Jan 20 '10 at 10:15
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`table_structure` seems to be specific to the sqlite adapter. – Kelvin Feb 02 '12 at 18:56
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For Rails4 use Model.column_names to list table columns – Stephen Provis Jun 08 '15 at 21:02
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Also in Rails 4, you can just use _ModelName_ to get a list of the columns and their data types. – themattkellyshow Apr 11 '16 at 11:35

hamster ham · Answer 2 · 2015-11-25T12:11:01.127

33

I hope my late answer can be of some help.
This will go to rails database console.

rails db

pretty print your query output

.headers on
.mode columns
(turn headers on and show database data in column mode )

Show the tables

.table

'.help' to see help.
Or use SQL statements like 'Select * from cars'

edited Nov 25 '15 at 12:11

answered Nov 25 '15 at 12:05

hamster ham

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'rails dbconsole' puts you in the command line interpreter (CLI) of whatever database engine you're using... the above are SQLite commands... Postgres, for example, would use '\dt' to list tables... – Tom Hundt Jun 03 '16 at 21:21
is there a way to ensure that every time you don't have to apply .headers on and .more columns when running rails db – Mark Nov 06 '17 at 12:25
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TIL. after 12 years, didn't know `rails db` is a thing. lul – Tim Kretschmer Oct 16 '21 at 09:55

score 9 · Answer 3 · answered Apr 10 '15 at 17:17

9

To get a list of all model classes, you can use ActiveRecord::Base.subclasses e.g.

ActiveRecord::Base.subclasses.map { |cl| cl.name }
ActiveRecord::Base.subclasses.find { |cl| cl.name == "Foo" }

answered Apr 10 '15 at 17:17

DomQ

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Also: `ActiveRecord::Base.descendants.map(&:name)` – valk Sep 09 '16 at 11:13

score 4 · Answer 4 · answered Sep 22 '16 at 07:14

4

You can use rails dbconsole to view the database that your rails application is using. It's alternative answer rails db. Both commands will direct you the command line interface and will allow you to use that database query syntax.

answered Sep 22 '16 at 07:14

Mestica

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score 1 · Answer 5 · answered Jun 22 '18 at 13:30

1

Run this:

Rails.application.eager_load!

Then

ActiveRecord::Base.descendants

To return a list of models/tables

answered Jun 22 '18 at 13:30

stevec

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score -3 · Answer 6 · edited Jun 24 '15 at 16:01

-3

Its a start, it can list:

models = Dir.new("#{RAILS_ROOT}/app/models").entries

Looking some more...

edited Jun 24 '15 at 16:01

JP Silvashy

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answered Jan 20 '10 at 00:24

rtfminc

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by doing this you just list models files what if tables are exists in db and do not have model fild in the models dir !! – abo-elleef Oct 31 '13 at 05:58

Rails: How to list database tables/objects using the Rails console?

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