rails sqlite adapter error

问题:

I'm following the instructions in rails tutorial and got stuck when trying to use the scaffold command.

When running:

rails generate scaffold User name:string email:string  

I get the error:

C:/RailsInstaller/Ruby1.9.2/lib/ruby/gems/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_specification.rb:71:in `rescue in establish_connection': Please install the sqlite3 adapter: `gem install activerecord-sqlite3-adapter` (can't activate sqlite3 (~> 1.3.4), already activated sqlite3-1.3.3-x86-mingw32. Make sure all dependencies are added to Gemfile.) (RuntimeError)

Running:

gem install activerecord-sqlite3-adapter

I got the error:

ERROR:  Could not find a valid gem 'activerecord-sqlite3-adapter' (>= 0) in any repository
ERROR:  Possible alternatives: activerecord-jdbcsqlite3-adapter, activerecord-sqlserver-adapter, activerecord-nulldb-adapter, activerecord-spatialite-adapter, activerecord-simpledb-adapter

My Gemfile looks like this:

source 'http://rubygems.org'
gem 'rails', '3.1.0'  
gem 'sqlite3', '1.3.3'  
...

I'm running on Windows 7 x64 OS.

Any ideas?

回答1:

Ok I found the problem. I noticed that my Rails installation has both SQLite 1.3.3 and 1.3.4 I changed my Gemfile from:

gem 'sqlite3', '1.3.3'

to:

gem 'sqlite3', '1.3.4'

That solved the problem. Thanks @holger-just for pointing me to the relevant line in the error message in their answer.

回答2:

suggested install command:

gem install activerecord-jdbc-sqlite3-adapter

actual install command:

gem install activerecord-jdbcsqlite3-adapter

Reference: http://kenai.com/jira/browse/ACTIVERECORD_JDBC-19

回答3:

The important part of your error message is this snippet:

can't activate sqlite3 (~> 1.3.4), already activated sqlite3-1.3.3-x86-mingw32. Make sure all dependencies are added to Gemfile.

To fix that, you should always run your commands through bundle exec like so

bundle exec rails generate scaffold User name:string email:string 

That way, you give bundler to take full control over your $LOAD_PATH which will probably resolve these issues.

回答4:

i had this error too, buy my problem was slightly different. the issue is that sqlite3-ruby is deprecated, to be replaced by sqlite3. in michael hartl's webcast, he still used the old sqlite3-ruby.

I edited my gemfile to use sqlite 1.3.4 instead of sqlite3-ruby 1.3.1. re-ran bundle install, and voila, problem solved!

回答5:

Instead of

gem install activerecord-sqlite3-adapter

run

gem install sqlite3

回答6:

Also on Rails Tutorial, ran:

  $ rake db:migrate

Got the following error:

Please install the sqlite3 adapter: gem install activerecord-sqlite3-adapter (sqlite3 is not part of the bundle. Add it to Gemfile.).

Ran:

$ gem install activerecord-sqlite3-adapter

Got:

ERROR: Could not find a valid gem 'activerecord-sqlite3-adapter' (>= 0) in any repository

Changed Gemfile according to one of the answers above:

gem 'sqlite3', '1.3.4'

Got another error so had to install:

$ gem install sqlite3 -v '1.3.4'

Tried running $ rake db:migrate again, but got another error, this time resembling the answer above:

Please install the sqlite3 adapter: gem install activerecord-sqlite3-adapter (can't activate sqlite3 (~> 1.3.5), already activated sqlite3-1.3.4. Make sure all dependencies are added to Gemfile.)

So changed Gemfile to:

gem 'sqlite3', '1.3.5'

And got another error message to make sure 'gem install sqlite3 -v '1.3.5' succeeds (wtf?! alright again). Installed it successfully, ran bundle install.

Tried running:

$ rake db:migrate

Nothing happened, so tried:

$ bundle exec rails generate scaffold User name:string email:string

Per another suggestion above. And it finally worked. The tutorial warned of a laborious setup process, but I felt like I had to mix and match from at least 5 other people. Hope this helps the next person.