I have a rails app on heroku. I recently updated the database by changing a column name and also adding a new column. Both the tasks were done using migration files. The changes were reflected properly on my local system. Also when I ran rake migration on heroku and restarted the app there was no problem. I can see the changes in the database schema by remotely connecting using pgadmin. But I cannot use the columns that are modified. When I edit my code to use the new columns application says that there are no such columns.
Thanks
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I have created an application with Ruby and Rails. The thing is that when I was develpoing it, I had some problems with the migrations, because I created them but with a wrong syntax. What happened is that I deleted some of the files because sold migrations that didn´t work had the same name than the new ones, but in the middle of that I accidentally deleted some of the migrations (obviously after running rails db:migrate) that the project uses actually. So for instance, i have the Service table, which is related to the Reservation table because Service has reservation_id, but i don´t have the migration file that says AddReservationIdToService.
So now I want to use Heroku for production. the thing is that O have to change to postgresql because Heroku doesn't support sqlite. So i have to run the de:migrate again to create the tables and relationships in the new DB, but I need the files that I explained that I deleted. The question is:
Can I create the migrations manually, so when i run db:migrate for postgres the full structure of the database is created without lacking relations?
You don't really need the migrations to recreate the existing DB -- in fact it's not a good idea to try for a couple of reasons (including the missing migration file problem you encountered). You can simply run:
bin/rails db:schema:load
to populate a new database from the existing schema. If for some reason you haven't got a db/schema.rb checked under version control you can run:
bin/rails db:schema:dump
against the sqlite version to re-create a fresh schema file from the database.
You can also keep your migrations list tidy by occasionally zapping really old migrations, since all the cumulative changes are captured in the schema file.
Yes, you might create another couple of migration files.
Certify you have now the tables you wish locally with your sqlite. Draw these table in a piece of paper (or where it be the best fr you), then check this official API documentation of Rails.
Delete all migrations made before and create another according to the tables you drew.
The workflow is gonna be like:
1) "I need to create a table called Reservation, where is it shown on the documentation?"
2) "I need a table called Service, where is it shown on the documentation?
3) "I need to add a column with a foreign key to service named reservaton_id, how does this documentation says it?
For all this steps above, create the correspondent migration file as you normally have done.
The main difference here is not to run the migration locally. Instead, push your new version app to your heroku remote branch and there you run the migration, like:
heroku run rails db:migrate
Remember to not run this same migration locally because you already have these tables locally.
The last two advise is:
1) If your migration doesn't go as you expect, don't delete the migration file. Instead, run rails db:rollback and try again.
2) Keep tracking your migration files on the same branch of your version control.
For a Ruby-on-Rails app that I'm hosting through Heroku, I recently downloaded a backup, restored it locally and then added data to the database from outside sources. That all worked fine.
After the updated database was pushed to Heroku using heroku pg:push <localdbname> HEROKU_DATABASE_URL --app <appname> the app was working fine and I could see the data that was newly added.
However today when I tried to log in to the app on Heroku, I was getting error messages. In my log file I saw this error:
ActionView::Template::Error (Unknown primary key for table ...
According to this SO post: Getting "Unknown primary key for table" while the ID is there
one user was able to get around this problem by resetting and pushing the database to Heroku several times. However, that hasn't worked for me. I've tried to reset and push the database at least 4 times now.
One possibility is that my local postgres database is using version 9.6 and the app is using version 9.4. The Heroku database is a Hobby-Basic database. There is documentation from Heroku on how to upgrade the Postgres version but it's not totally clear from their example what I would need to do. I'm guessing that I basically need to create a new database, copy the data from the old to the new and then destroy the old. Has anyone done this before? Is there a fee associated with doing so? And has upgrading the version of Postgres remotely fixed this issue for other people?
I have ran into similar issues before. I was creating a postgres database outside of rails in RazorSQL. I imported data from outside sources and when I ran it locally everything worked fine. When it came to deployment I ran into all sorts of issues.
I created tables outside of rails thus no migrations were created. I had to recreate the tables by deleting the current model and generating a new model which is a copy of the old one only this time a migration is created for example:
rails generate model ad name:string description:text price:decimal
seller_id:integer email:string img_url:string
I needed to import data from the database I had already created and before I did anything I actually created a seed file using this gem https://github.com/rroblak/seed_dump. All I had to do when I created the model again (remember to delete the model and recreate it) was run rake db:seedand it pulled the data in.
3.The last thing I had to do was insert the assocations in the models for example in a owner model putting in has many: customersto connect the customer model.
Another scenario was I ran a query in RazorSQL and generated a new table from the query and imported it into postgres. The problem was it was only a table from results thus it did not have a primary key. I had to manually create that in postgres using ALTER TABLE test1 ADD COLUMN id SERIAL PRIMARY KEY; This gave me an auto incrementing primary key field and I have to give credit to this answer which helped me https://stackoverflow.com/a/2944561/7039895.
Hope this helps.
According to the docs, you several choices of how to upgrade your database. pg:copy and pg:upgrade.
In your case, I recommand pg:copy: this is easier but required your database to be "off" while your doing the upgrade. This should not be an issue since your database is not currently working.
pg:upgrade should only be used when the downtime required for a PG copy
upgrade is unacceptably long for your business.
Upgrade with PG copy: (All the steps are explain in depth in the link)
Provision new database
You need to create a new database, it will be automatically using the last version of postgresql for heroku (in your case 9.6)
heroku addons:create heroku-postgresql:standard-0
Prevent new database updates
Stop you current database from writing mode to avoid corrupted data while copying to the new
heroku maintenance:on
Transfer data to new database
You need to copy all the data from the old DB to the new.
heroku pg:copy DATABASE_URL HEROKU_POSTGRESQL_PINK --app sushi
Promote new database
You need to notify heroku that you will use the new DB and not the old one.
heroku pg:promote HEROKU_POSTGRESQL_PINK
Last step: Make application active
Everything should be good by now, just make your DB active so it can save new query.
heroku maintenance:off
As you can see, all the steps are straightforward. Therefore, if upgrading you version of postgreSQL doesn't solve the issue, you can still switch back to the old one before removing it.
Pricing
I think it depends of your subscription already (Hobby, Standard or Premium) https://www.heroku.com/pricing. It may be free, or cheap, but I think it also depends of the size of your DB.
To be sure it won't cost you too much, I'm sure you can ask directly to Heroku support https://devcenter.heroku.com/articles/paid-support.
I recently deployed a website to heroku and I am having problems with the database. I am using ruby on rails and when I first created my local databases I used SQLite. When deploying to heroku I had to change my databases to Postgres and in the process several migration files got removed and changed into a single migration. Now, when I run the postgres database on my localhost, I am still seeing all of the columns in my database, but when I visit the page on heroku one of the columns is missing.
I have checked both my local console and the heroku console and the databases are now different. The local console includes all of the columns in the database and the heroku console is missing one of the columns in the database, but is generating all of the other columns correctly. I have tried running a rake task on heroku and have pushed the most recent changes to heroku.
I tried to to add an additional migration to add the missing column to the database, but whenever I try to rake the migration it tells me that attribute already exists. Any help I can get is appreciated!
The best way to set up your database on heroku is with
rake db:schema:load
From the guides on migrations
Migrations, mighty as they may be, are not the authoritative source
for your database schema. That role falls to either db/schema.rb or an
SQL file which Active Record generates by examining the database. They
are not designed to be edited, they just represent the current state
of the database.
There is no need (and it is error prone) to deploy a new instance of
an app by replaying the entire migration history. It is much simpler
and faster to just load into the database a description of the current
schema.
I have made quite a large upgrade to my app. I have older version deployed on Heroku at the moment. Problem is that I have added/removed quite few migrations in the process of making my app more modular. I do not want to lose my registered user table that is already up on Heroku while deploying the update. Are there any tips someone can offer on how to preserve my user table while upgrading the app? I do have backup add-on installed but I have no clue what to do with that file.
You should then setup your migrations more carefully since that one, which is last presented on the heroku server. So, when:
you are adding a column, just setup defualt value
you remove the column, you shell export data to (for example) YAML, and store it in the tmp/.
you are reconstructing parts of the colunms by adding and remove some of them, in migration carefully copy required data from older column (prepared to deletion) to newly created ones.
If you're that concerned about deploying I think you might need to declare migration bankruptcy.
Create a new migration that drops the current schema and copy the new database schema into it
Dump out the contents of your database as CSV ( https://coderwall.com/p/jwtxjg/simple-export-to-csv-with-postgres ) or using Rails to dump in some other way (YAML etc.)
Write a Rake task to parse the data dump into your new schema
Set up a new database on Heroku Postgres (this does not delete the old data)
Do a dry run locally to make sure it all works
Promote the new database to DATABASE_URL
Deploy, migrate, run the Rake task
Not very nice and not something you can roll back from easily if it goes wrong.
I was able to push my Ruby on Rails app with MySQL(local dev) to the Heroku server along with migrating my model with the command heroku rake db:migrate. I have also read the documentation on Database Import/Export. Is that doc referring to pushing actual data from my local dev DB to whichever Heroku's DB? Do I need to modify anything in the file database.yml to make it happen?
I ran the following command:
heroku db:push
and I am getting the error:
Sending data
2 tables, 3 records
!!! Caught Server Exception | ETA: --:--:--
Taps Server Error: PGError ERROR: duplicate key value violates unique constraint
"unique_schema_migrations"
I have 2 tables, one I create for my app and the other schema_migrations. The total number of entries among the 2 tables is 3. I'm also printing the number of entries I have in the table I have created and it's showing 0.
Any ideas what I might be missing or what I am doing wrong?
EDIT:
I figured out the above, Heroku's DB already have schema_migrations the moment I ran migrate.
New question: Does anyone know how I can exclude data from a specific table from being pushed to Heroku DB. The table to exclude in this case will be schema_migrations.
Not so good solution:
I googled around and someone else was having the same issue. He suggested naming the schema_migrations table to zschema_migrations. In this way data from the other tables will be pushed properly until it fails on the last table. It's a pretty bad solution but will do for the time being.
A better solution will be to use an existing Rails command which can reset a specific table from a database. I don't think Rake can do that.
Two possible options:
The heroku gem and the taps gem (which it uses to synchronize databases) are both open-source - you could fork them, alter the taps client API to support excluding tables from a push, then alter the heroku gem to use that new option.
You could write a wrapper script that uses pgdump to backup the schema_migrations table, drops that table, heroku pushes the database, then reloads the table.
This is kind of a guess based on the error you're getting, but push looks like it grabs the schema and the data. I'd try push to an empty database.
I've just deployed a Rails 3 beta app to heroku on their new bamboo server. I can now upload data from my local dev machine to the heroku database by doing:
heroku rake db:fixtures:load test/fixtures/my_model.yml
The data is then properly propagated in the Heroku database. Even though I specified a specific data file, it automatically pushes data from my other yaml files. It probably has something to do with my model relationships.
If your databases are out of sync you can always reset the Heroku database before pushing using
heroku db:reset
To push/pull from specific tables
heroku db:pull --tables logs,tags
http://blog.heroku.com/archives/2010/4/21/supporting_big_data_part_1