I'm using on online tutorial for homebrew to get Ruby on Rails working
https://gorails.com/setup/osx/10.11-el-capitan
Toward the end I am told to change config/database.yml's username to be the same as your OSX user account. I am unclear on how exactly to be accessing this infroamtion, and then even executing it.
I need to update the config/database.yml file to match the database username and password and I'm not sure how to be doing it from the terminal. Thank you!!
postgresql requires a role and a password in database.yml.
This tells you how to open postgresql console from terminal and create a role.
Step 1: Enter postgresql console from terminal
psql -d postgres -U username
Step 2: Create Role
create role rolename with createdb login password 'password1';
Use rolename as username and password1 as password in database.yml.
I am working with a Rails 4 app, I am using PSQL both in my development and production. Due to some reason I have to work with a new computer/laptop so I set up Rails environment in it and cloned my app into it, but what I really require is that, I need my existing databse with data in it, how to do it ?
To do this you need to create a dump on system 1 and restore it on system 2, here are the steps:
sudo -u postgres pg_dump <DB_NAME> > dump - creating a file dump
Copy this file via dropbox or whatever to another system.
sudo -u postgres psql <DB_NAME> < dump - copy the new created dump to new system.
Note:
You should have empty created database on your new system, or you can use dataonly dump passing the --data-only to pg_dump command.
Also you can read documentation for pg_dump to find any other options which you might need.
I chose postgresql for my database for rails but i ran into an apparently common error where 'FATAL: role "app" does not exist' when i try to run rake db:create:all. I found two solutions but im not sure which one is the right one to use. One website says to
su -
su - postgres
createuser -s Application
exit
exit
while the other says to
su - postgres
create role myapp with createdb login password 'password1'
what's the difference between the two? and which one should i use?
You should use this for the development environment only
Login in postgres console:
$> sudo -u postgres psql
create user with name rails and password:
=# create user rails with password 'password';
make user rails superuser:
=# alter role rails superuser createrole createdb replication;
create database projectname with owner rails:
=# create database projectname owner rails;
in database.yml:
development:
adapter: postgresql
encoding: unicode
database: projectname
pool:
username: rails
password: password
To create a user type this in your console
createuser
Enter the username and make it a superuser
Also you could add a password also by adding pwprompt to createuser like this
createuser --pwprompt
Next you enter pgsql as postgres and create your database
sudo -u postgres psql postgres
create database db_name owner user_name;
Hope it helps
Refer this site for more details
https://www.digitalocean.com/community/articles/how-to-install-and-use-postgresql-on-ubuntu-12-04
The second option is invalid. That does not work.
The first one:
I don't recommend the first one and depending on your operating system some of the steps are unnecessary.
You become a superuser and make the shell a login shell (as if you would log in directly). I think it is risky and not necessary. Why not suing directly to postgre user (that's just a matter of setup)?
You become postgre and make the shell a login shell
You create a superuser Application in PostgreSQL. So you have the privileges of a superuser for your application. I think that is risky too. Superuser for an application is very bad. Often you need createdb, login and password to get started and other privileges, if ever needed, can be added/revoked later.
You quit the postgres shell session.
You quit the superuser shell session
The second one:
That's not correct. You forget to execute psql command as second step. The second command would become the third. It would be like that.
You become postgres and make the shell a login shell
You log into postgres command shell by default with user postgres
You create a role myapp with options createdb, login and (usually by default encrypted) password with value password1.
The difference is that the first one grants superuser privileges to the Application role while the second grants only the listed permissions to the myapp role.
The second option is more secure. Among the two option opt for the seoconde one.
Note: In PostgreSQL a user is simply a role with login permission. It's more of a conceptual distinction. Technically a user and role are pretty much the same as far as I know.
I have installed PostgreSQL on my Mac OS Lion, and am working on a rails app. I use RVM to keep everything separate from my other Rails apps.
For some reason when I try to migrate the db for the first time rake cannot find the postgres user. I get the error
FATAL: role "postgres" does not exist
I have pgAdmin so I can clearly see there is a postgres user in the DB - the admin account in fact - so I'm not sure what else to do.
I read somewhere about people having issues with PostgreSQL because of which path it was installed in, but then I don't think I would have gotten that far if it couldn't find the db.
Actually, for some unknown reason, I found the issue was actually because the postgresql role hadn't been created.
Try running:
createuser -s -r postgres
Note that roles are the way that PostgreSQL maintains database permissions. If there is no role for the postgres user, then it can't access anything. The createuser command is a thin wrapper around the commands CREATE USER, CREATE ROLE, etc.
Recently i got this problem immediately after installing postgres.
If it comes immediately after installation, you might be missing the default user, postgres.
In that case, you can create default user postgres using below command.
createuser -s -U $USER
Ex: createuser -s -U $USER
enter your required role name: postgres
enter password for your the user:
It will prompt you to enter required database role name and password
Once you complete the process, you can login to the postgres console using below command
psql -U 'your_database_name'
Ex: psql -U postgres
Here, You need to enter the password if you have given any, while creating the user.
Hope it helps :)
I was on OSX 10.8, and everything I tried would give me the FATAL: role "USER" does not exist. Like many people said here, run createuser -s USER, but that gave me the same error. This finally worked for me:
$ sudo su
# su postgres
# createuser -s --username=postgres MYUSERNAME
The createuser -s --username=postgres creates a superuser (-s flag) by connecting as postgres (--username=postgres flag).
I see that your question has been answered, but I want to add this answer in for people using OSX trying to install PostgreSQL 9.2.4.
This message pops up, when the database user does not exist. Compare the manual here.
Multiple local databases cannot be the explanation. Roles are valid cluster-wide. The manual again:
Note that roles are defined at the database cluster level, and so are
valid in all databases in the cluster.
You must be ending up in another database-cluster. That would be another server running on the same machine, listening to a different port. Or, more likely, on a different machine.
Could it be that the message comes, in fact, from the remote server?
I met this issue right on when I first install the Heroku's POSTGRES.app thing. After one morning trial and error i think this one line of code solved problem. As describe earlier, this is because postgresql does not have default role the first time it is set up. And we need to set that.
sovanlandy=# CREATE ROLE postgres LOGIN;
You must log in to your respective psql console to use this psql command.
Also noted that, if you already created the role 'postgre' but still get permission errors, you need to alter with command:
sovanlandy=# ALTER ROLE postgres LOGIN;
Hope it helps!
In the Heroku documentation; Getting started whit rails 4, they say:
You will also need to remove the username field in your database.yml
if there is one so: In file config/database.yml remove: username:
myapp
Then you just delete that line in "development:", if you don't pg tells to the database that works under role "myapp"
This line tells rails that the database myapp_development should be
run under a role of myapp. Since you likely don’t have this role in
your database we will remove it. With the line remove Rails will try
to access the database as user who is currently logged into the
computer.
Also remember to create the database for development:
$createdb myapp_development
Repleace "myapp" for your app name
The installation procedure creates a user account called postgres that is associated with the default Postgres role. In order to use Postgres, you can log into that account. But if not explicitly specified the rails app looks for a different role, more particularly the role having your unix username which might not be created in the postgres roles.
To overcome that, you can create a new role, first by switching over to the default role postgres which was created during installation
sudo -i -u postgres
After you are logged in to the postgres account, you can create a new user by the command:
createuser --interactive
This will prompt you with some choices and, based on your responses, execute the correct Postgres commands to create a user.
Pass over a role name and some permissions and the role is created, you can then migrate your db
Could you have multiple local databases? Check your database.yml and make sure you are hitting the pg db that you want. Use rails console to confirm.
My answer was much more simple. Just went to the db folder and deleted the id column, which I had tried to forcefully create, but which is actually created automagically. I also deleted the USERNAME in the database.yml file (under the config folder).
In Ubuntu local user command prompt, but not root user, type
sudo -u postgres createuser username
username above should match the name indicated in the message "FATAL: role 'username' does not exist."
Enter password for username.
Then re-enter the command that generated role does not exist message.
I ended up here after attempting to follow Ryan Bate's tutorial on deploying to AWS EC2 with rubber. Here is what happened for me:
We created a new app using "
rails new blog -d postgresql
Obviosuly this creates a new app with pg as the database, but the database was not made yet. With sqlite, you just run rake db:migrate, however with pg you need to create the pg database first. Ryan did not do this step. The command is rake db:create:all, then we can run rake db:migrate
The second part is changing the database.yml file. The default for the username when the file is generated is 'appname'. However, chances are your role for postgresql admin is something different (at least it was for me). I changed it to my name (see above advice about creating a role name) and I was good to go.
Hope this helps.
After a bunch of installing and uninstalling of Postgres, here's what now seems to work consistently for me with Os X Mavericks, Rails 4 and Ruby 2.
In the database.yml file, I change the default usernames to my computer's username which for me is just "admin".
In the command line I run rake db:create:all
Then I run rake db:migrate
When I run the rails server and check the local host it says "Welcome aboard".
You might be able to workaround this by running initdb -U postgres -D /path/to/data or running it as user postgres, since it defaults to the current user. GL!
I'm having problems getting testing to work with Postgresql and Rails 3.
Both development and production databases I can get to work fine, however the test database throws the following errors when I run rake or db:test:prepare, etc.
PGError: ERROR: source database "template1" is being accessed by other users
Update
Googling around, it seems that one should use template0 instead of template1 when using createdb to create a new database in Postgres. In typical “So I’ll remove the cause. But not the symptom” fashion, I found vendor/rails/railities/lib/task/databases.rake and changed line 109 to read:
createdb #{enc_option} \
-U "#{abcs["test"]["username"]}" \
-T template0 #{abcs["test"]["database"]}
But I don't really wanna do that, as I'm using Rails as a GEM, any one know of another work around or fix?
database.yml:
development:
adapter: postgresql
encoding: unicode
database: test1234_development
pool: 5
username: holden
password: postgres
test:
adapter: postgresql
encoding: unicode
database: test1234_test
pool: 5
username: holden
password: postgres
Full error:
NOTICE: database "test1234_test" does not exist, skipping
PGError: ERROR: source database "template1" is being accessed by other users
DETAIL: There are 1 other session(s) using the database.
: CREATE DATABASE "test1234_test" ENCODING = 'unicode'
Short story: CREATE DATABASE works by copying an existing database. PostgreSQL won't let you copy a database if another session is connected to it. If template1 is being accessed by other users, CREATE DATABASE will fail.
The question you need to answer: Why are other sessions connected to template1?
The difference between template0 and template1
At the point you initialize a database cluster, template0 and template1 are the same. Any location-specific stuff you want to make available to every database you create by using CREATE DATABASE should go into template1. So, for example, if you add the procedural langauge PL/python to template1, every database you create later will include PL/python.
The database template0 is intended to be a "virgin" template. It should contain only standard database objects--the ones created by initializing the cluster. As a "virgin" template, it should never be changed. Never.
If you need to specify encoding and locale settings (collation), then you can do that by copying template0. You can't do that by copying template1.
This problem occur when you had logged(psql template1 or psql template0) in template1 and template0 database and exit using below command.
Ctrl + z
Better way exist from db use below postgres command then problem will not create:
\q + enter
There are 2 solutions, If have problem.
Solution - 1
Restart posgres service like.
sudo service postgresql restart
Solution - 2
sudo ps aux | grep template1
Make sure don't delete this processes
postgres 8363 0.0 0.0 111760 7832 pts/11 T 09:49 0:00 /usr/lib/postgresql/9.5/bin/psql template1
ankit 18119 0.0 0.0 14224 976 pts/14 S+ 12:33 0:00 grep --color=auto template1
rest of process should be kill using below command.
sudo kill -9
Now try to create db again.
Hope this help you.
Ankit H Gandhi.
Just restart the service of database.
I restarted my system and the error was still showing. However, I followed the steps below to sort it out.
Stop all processes using the postgres port 5432 by doing this in command prompt (Admin): Type netstat -ano in command prompt. Find the pid with Local Address of 0.0.0.0:5432. Then use taskkill /pid {pid} /f to kill the task.
Start the postgres service in windows services.
I also got this error while trying to reset the database while I had the default Ruby on Rails server WEBrick running:
$ bin/rake db:reset
PG::Error: ERROR: database "dev" is being accessed by other users
DETAIL: There is 1 other session using the database.
: DROP DATABASE IF EXISTS "dev"
The other user here was the running Rails app. After shutting down the server with CTRL + c, I was able to re-run the database reset command without any problems.
It makes sense too. You can't drop the database if someone else is currently connected to it, as Mike Sherrill also points out.
Solution for me was to delete old server and create a new one from Postgresql administration web interface. Could now create new database without this error.
I was also stuck setting up postgres on ruby on rails project, ensure that you have installed pg locally and created a user with its password then on your database.yml should have:- host: localhost, password: (set password) then run:
$ rails db:create
$ rails db:migrate