I have a problem I can't figure out here. I'm writing a ruby script that deals with an sqllite database.
require 'rubygems'
require 'sqlite3'
require 'active_record'
ActiveRecord::Base.establish_connection(
:adapter => "sqlite3",
:database => "../database/my.db"
)
class KeyWord < ActiveRecord::Base
set_table_name "keywords"
end
# THIS STATEMENT WORKS (finds the first record, returns "ruby") :
KeyWord.find(1).keyval
# THOSE STATEMENTS RETURN NO RESULT :
KeyWord.find(:all, :conditions => {:keyval => "ruby"})
KeyWord.find_by_sql("SELECT * FROM keywords WHERE keyval='ruby'")
KeyWord.find_by_keyval("ruby")
This is how the table was created :
create_table :keywords do |table|
table.column :keyval, :text
end
Does anyone know where this could come from ?
Thanks,
R.
I see a couple of issues here.
I'm not sure why you're manually setting your table name.
ActiveRecord assumes that your model name is camelCased. So... AR
would, by default, search for a table called key_words. Why not just
go with that?
Pay attention to which version of active record you are
using. Passing in conditions is deprecated. You should be using the
.where syntax. So... you would need to do KeyWord.where(:keyval
=> 'ruby').first or end in .all for a collection of results.
If you are just fooling around, you can use sqlite3 in memory.
ActiveRecord::Base.establish_connection( adapter: 'sqlite3',
database: ":memory:")
Also don't forget to define your schema!
Here is full code w/ more modern syntax.
require 'rubygems'
require 'sqlite3'
require 'active_record'
ActiveRecord::Base.establish_connection( adapter: 'sqlite3', database: ":memory:" )
ActiveRecord::Migration.verbose = false
ActiveRecord::Schema.define(version: 2) do
create_table :key_words do |t|
t.text :keyval
end
end
class KeyWord < ActiveRecord::Base
end
Keyword.create!(:keyval => 'ruby')
# THESE STATEMENTS WORK:
KeyWord.find(1).keyval
KeyWord.where(:keyval => 'ruby').first
KeyWord.where(:keyval => 'ruby').all
KeyWord.find_by_sql("SELECT * FROM key_words WHERE keyval='ruby'")
KeyWord.find_by_keyval("ruby")
Related
I want to read entrys from a Database using active_record and keep getting diffrent Errors like: Name error and can't find the database or it can't execute the query.
so my question here is how do i read from a database or execute SQL-queries and for example write the result into a variable?
require 'rubygems'
require 'sinatra'
require 'active_record'
require 'sqlite3'
ActiveRecord::Base.establish_connection(
:adapter => "sqlite3",
:database => "test.db"
)
class Article < ActiveRecord::Base
end
#ActiveRecord::Migration.create_table :users do |t|
# t.string :name
#end
class App < Sinatra::Application
end
get '/' do
output = users.select(:all)
f = File.open('name','a'); f.write(output); f.close
#puts User.first
To read the data from the users table, you'd simply do:
class User < ActiveRecord::Base
end
get '/' do
#users = User.all
puts "Grabbed #{#users.size} user(s) from database"
end
I am trying to create active record using Sinatra and Sinatra/active record, my migrations are getting migrated to the Postgres database but tables are not getting created in the database, I went through all the possible solutions on stack overflow but its of no use. I tried even deleting my migration files from db/migrate folder but still the same output. What must be the error
Gemfile
source 'https://rubygems.org'
gem "sinatra"
gem "pg" #for postgres
gem "activerecord"
gem "sinatra-activerecord"
config.ru
require "./app"
run Sinatra::Application
rakefile.rb
require "./app"
require "sinatra/activerecord/rake"
app.rb
require 'sinatra'
require 'sinatra/activerecord'
db = URI.parse('postgres://project1:project1#localhost/*****')
ActiveRecord::Base.establish_connection(
:adapter => db.scheme == 'postgres' ? 'postgresql' : db.scheme,
:host => db.host,
:username => db.user,
:password => db.password,
:database => db.path[1..-1],
:encoding => 'utf8'
)
class Note < ActiveRecord::Base
end
class CreateNotes < ActiveRecord::Migration
def up
create_table :notes do |t|
t.string :title
t.text :body
t.timestamps
end
end
def down
drop_table :notes
end
end
output of migration
user#user-Inspiron-5520:~/rails-apps/project1$ rake db:migrate
== 20150704053019 CreateNotes: migrating ======================================
== 20150704053019 CreateNotes: migrated (0.0000s) =============================
db output (psql)
\dt
List of relations
Schema | Name | Type | Owner
--------+-------------------+-------+-----------
public | schema_migrations | table | project1
(1 row)
project1=# select * from schema_migrations;
version
----------------
20150704053019
(1 row)
note: Project1 user is a super user with all privileges
EDIT
Migrations file 20150704053019_create_notes.rb
class CreateNotes < ActiveRecord::Migration
def change
end
end
I would first like to note that #limekin was the first to get the answer, commenting:
The migration you are using to create notes table is actually kept in app.rb. But the migrate task looks for migrations inside db/migrate. If the migration file you gave at the bottom is inside the right directory, then move the migration definition from app.rb to there.
I will just go into a bit more detail. The function that you are using to create the table belongs in the migration file, because a migration is what creates, changes and deletes tables, columns, and records.
So to solve your issue just move the function up in your app file into the change function in your migration file.
I use the ActiveRecord-gem for accessing a sqlite3-database, all without Rails. I use it like this:
ActiveRecord::Base.establish_connection(
:adapter => "sqlite3", :database => name_file )
ActiveRecord::Schema.define do
if ! table_exists? "db_table"
do_something
end
end
And then I get an output like
-- table_exists?("db_table")
-> 0.0048s
Which I don't want. According to different posts, a simple
ActiveRecord::Base.logger = nil
should do the trick. But this is already nil...
Those look like migration messages. This should help:
ActiveRecord::Migration.verbose = false
I'm working on a Gem that contains a migration generator and a bunch of models, classes, etc that utilize the tables created as part of the migration.
Although testing the migration generator itself is easy enough - there's loads of tutorials around for getting that done, what i'm trying to work out is how to actually run the migration on the test DB so I can later test how the gem interacts with the test data?
Since the gem doesn't have a schema.rb, I wasn't sure how to go about doing it.
This is how I run migrations in code;
ActiveRecord::Base.establish_connection(:adapter => "sqlite3", :database => ":memory:")
ActiveRecord::Migration.verbose = false
#migration = Class.new(ActiveRecord::Migration) do
def change
create_table :users, :force => true do |t|
t.string :roles_mask
end
create_table :user_without_roles, :force => true do |t|
t.string :roles_mask
end
create_table :user_without_role_masks, :force => true do |t|
end
end
end
#migration.new.migrate(:up)
If you have a string containing your generated migration you could do something like this in your test setup;
ActiveRecord::Base.establish_connection(:adapter => "sqlite3", :database => ":memory:")
ActiveRecord::Migration.verbose = false
# Or however you intend to grab the output of the migration generator
migration_string = ERB.new(File.read(<file name here>)).result
migration = Class.new(ActiveRecord::Migration)
migration.class_eval(migration_string)
migration.new.migrate(:up)
That should give you a migrated database using the migration you've generated.
You can do something like this:
I am going to assume you're using ActiveRecord. So in your test helper you should setup a in-memory database:
require 'active_record'
# Connection must be establised before anything else
ActiveRecord::Base.establish_connection(
:adapter => defined?(JRUBY_VERSION) ? 'jdbcsqlite3' : 'sqlite3',
:database => ':memory:'
)
Then invoke the rake task within your test. This would look something like:
require 'rake'
requie File.expand_path('../Rakefile', __FILE__) # you'll need to modify this path to actually point to the Rakefile
Rake::Task['db:migrate'].invoke
The rake taks invocation is untested, but that should point you in the right direction.
The other option would be to just run the command:
%x{rake db:migrate}
I have the following ActiveRecord testcase that mimics my problem. I have a People table with one attribute being a date. I create a view over that table adding one column which is just that date plus 20 minutes:
#!/usr/bin/env ruby
%w|pp rubygems active_record irb active_support date|.each {|lib| require lib}
ActiveRecord::Base.establish_connection(
:adapter => "sqlite3",
:database => "test.db"
)
ActiveRecord::Schema.define do
create_table :people, :force => true do |t|
t.column :name, :string
t.column :born_at, :datetime
end
execute "create view clowns as select p.name, p.born_at, datetime(p.born_at, '+' || '20' || ' minutes') as twenty_after_born_at from people p;"
end
class Person < ActiveRecord::Base
validates_presence_of :name
end
class Clown < ActiveRecord::Base
end
Person.create(:name => "John", :born_at => DateTime.now)
pp Person.all.first.born_at.class
pp Clown.all.first.born_at.class
pp Clown.all.first.twenty_after_born_at.class
The problem is, the output is
Time
Time
String
When I expect the new datetime attribute of the view to be also a Time or DateTime in the ruby world. Any ideas?
I also tried:
create view clowns as select p.name, p.born_at, CAST(datetime(p.born_at, '+' || '20' || ' minutes') as datetime) as twenty_after_born_at from people p;
With the same result.
Well, after more investigation, I found that:
MySQL works:
%w|pp rubygems active_record irb active_support date|.each {|lib| require lib}
ActiveRecord::Base.establish_connection(
:adapter => "mysql",
:username => "root",
:database => "test2"
)
ActiveRecord::Schema.define do
create_table :people, :force => true do |t|
t.column :name, :string
t.column :born_at, :datetime
end
execute "create view clowns as select p.name, p.born_at, (p.born_at + INTERVAL 20 MINUTE) as twenty_after_born_at from people p;"
end
class Person < ActiveRecord::Base
validates_presence_of :name
end
class Clown < ActiveRecord::Base
end
Person.create(:name => "John", :born_at => DateTime.now)
pp Person.all.first.born_at.class
pp Clown.all.first.born_at.class
pp Clown.all.first.twenty_after_born_at.class
Produces:
Time
Time
Time
Reading the sqlite3 adapter source code, I found out that it uses PRAGMA table_info(table_name) to get the type information, and that does not return the types for views:
sqlite> pragma table_info('people');
0|id|INTEGER|1||1
1|name|varchar(255)|0||0
2|born_at|datetime|0||0
sqlite> pragma table_info('clowns');
0|name|varchar(255)|0||0
1|born_at|datetime|0||0
2|twenty_after_born_at||0||0
Therefore it may be a limitation of the adapter or just a sqlite3's views limitation. I have opened a ticket for ActiveRecord:
Also, quoting this mail in sqlite-users:
RoR should be using the
sqlite3_column_type() API to determine
the type of the values returned from a
query. Other APIs like
sqlite3_column_decltype() and pragma
table_info are returning other
information, not the type of the
result value.
Well, basically there is no datatime type in SQLite as opposed to MySQL. In your example you explicitly define types for the table but do not specify types for the view. That might be the problem. Can not check it since I have never touched ruby.