I have a Rails 4 app, where I am making a table that shows me what items I have in stock. Items that are not in stock are NOT displayed.
In my controller I do the following:
#stock = Stock.all
And In my view I have this:
<table>
<% #stock.each do |item| %>
<tr>
<td><%= item.id %></td>
<td><%= item.product.id %></td>
<td><%= item.product.description %></td>
</tr>
<% end %>
</table>
This is the outcome:
+---------------------------------------------+
| Stock ID | Product ID | Product description |
+---------------------------------------------+
| 1 | 63 | A cool wheel |
+---------------------------------------------+
| 2 | 63 | A cool wheel |
+---------------------------------------------+
| 3 | 63 | A cool wheel |
+---------------------------------------------+
| 4 | 26 | A red coat |
+---------------------------------------------+
| 5 | 26 | A red coat |
+---------------------------------------------+
| 6 | 99 | Something |
+---------------------------------------------+
| ... | ... | ... |
But I would like to have it grouped by amount. How could I achieve that?
This is what I would like to get
+---------------------------------------------+
| Amount | Product ID | Product description |
+---------------------------------------------+
| 3 | 63 | A cool wheel |
+---------------------------------------------+
| 2 | 26 | A red coat |
+---------------------------------------------+
| 1 | 99 | Something |
+---------------------------------------------+
| ... | ... | ... |
I thought this would do it, but it did not work:
.count(:all, group: "product_id")
ActiveRecord has a group function.
How to use it you can find it in the guides: http://guides.rubyonrails.org/active_record_querying.html#group
Hey you can try this way
#stock = Stock.joins(:product).select("count(product_id) as amount,products.id as product_id, products.description as product_description").group("product_id")
Related
I have this chain of models:
And I have a list of suboptions. I would like to group_by the suboptions by each of the above fathers.
So, it would be divided into Categories, which would be divided into activities, which would be divided into options. Do you see?
How can I do this??
Suboptions.all.group_by(???)
# or
Suboptions.all.order_by(????)
# or ????
Example:
Suboptions
+----+-----------+
| id | option_id |
+----+-----------+
| 1 | 1 |
| 2 | 2 |
| 3 | 2 |
| 4 | 4 |
| 5 | 3 |
+----+-----------+
Options
+----+-------------+
| id | activity_id |
+----+-------------+
| 1 | 1 |
| 2 | 2 |
| 3 | 1 |
| 4 | 3 |
+----+-------------+
Activities
+----+-------------+
| id | category_id |
+----+-------------+
| 1 | 1 |
| 2 | 2 |
| 3 | 1 |
+----+-------------+
Categories
+----+------+
| id | name |
+----+------+
| 1 | cat1 |
| 2 | cat2 |
+----+------+
then the search should return the suboptions with ids in the following order: [1,5,4,2,3]
( try to visualize it from the category to the suboption )
Depending on the size of the data set, sounds like you want to do a join, followed by an order
Suboption.joins(option: {activity: :category}).order('categories.name')
Will that work for you?
I populate book items into my Book model,
But I found there are many items have the same id.
So, how to create unique id for items. To prevent many items from having the same id ?
Here is the book model code
# encoding: utf-8
class Book < ActiveRecord::Base
attr_accessible :name, :isbn ,:price ,:comment ,:author ,:sale_type ,:publisher ,:sn ,:category
attr_accessible :location, :category, :release_date
validates_uniqueness_of :sn
Here are the part of my items
irb(main):058:0> Book.all[1..10]
+-----+------+-----+-----+------+------+-----+------+-----+-----+------+------+-----+------+
| id | pric | com | cre | upda | rele | loc | sn | isb | aut | sale | name | cat | publ |
+-----+------+-----+-----+------+------+-----+------+-----+-----+------+------+-----+------+
| 118 | 4543 | 作 | 201 | 2013 | 2006 | --- | 2124 | 978 | 趙 | prom | 求索 | 商 | 聯經 |
| 118 | 872 | 馬 | 201 | 2013 | 2013 | --- | 2124 | 978 | 黎 | prom | 告別 | 政 | 聯經 |
| 118 | 2105 | 某 | 201 | 2013 | 2012 | --- | 2124 | 978 | 吳 | prom | 複眼 | 政 | 夏日 |
| 118 | 301 | 作 | 201 | 2013 | 2006 | --- | 2124 | 978 | 王 | norm | 天香 | 歷 | 麥田 |
| 118 | 411 | 少 | 201 | 2013 | 2008 | --- | 2124 | 978 | 韓 | norm | 鞋癖 | 商 | 聯經 |
| 119 | 3751 | 有 | 201 | 2013 | 2010 | --- | 2124 | 978 | 紀 | prom | 私家 | 體 | 印刻 |
| 119 | 3361 | 文 | 201 | 2013 | 2010 | --- | 2124 | 978 | 林 | fix_ | 我不 | 體 | 印刻 |
| 119 | 1140 | 何 | 201 | 2013 | 2012 | --- | 2124 | 978 | 邁 | norm | 正義 | 體 | 雅言 |
| 119 | 888 | 一 | 201 | 2013 | 2007 | --- | 2124 | 978 | 福 | fix_ | 生命 | 商 | 究竟 |
| 119 | 3283 | 近 | 201 | 2013 | 2011 | --- | 2124 | 978 | 芮 | norm | 海拉 | 政 | 遠流 |
+-----+------+-----+-----+------+------+-----+------+-----+-----+------+------+-----+------+
here the rake code to generate my data
16 bk = Book.new(:sn => real_sn,:name => book_name, :isbn=>isbn,
17 :price =>Random.rand(200..5000), :location=>location, :category=>["商業","歷史","體育","政治"].sample,
18 :author => author, :sale_type => [:fix_priced, :normal, :promotion].sample, :publisher => publisher,
19 :release_date => rand(10.years).ago, :comment => comment
20 )
Columns in the table I use the Postgre DB
Column | Type | Modifiers
--------------+-----------------------------+----------------------------------------------------
id | integer | not null default nextval('books_id_seq'::regclass)
price | integer |
comment | text |
created_at | timestamp without time zone | not null
updated_at | timestamp without time zone | not null
release_date | text |
location | text |
sn | bigint |
isbn | bigint |
author | text |
sale_type | text |
name | text |
category | text |
publisher | text |
Indexes:
"books_pkey" PRIMARY KEY, btree (id)
The code above, does not save any record in the database, it just instantiate objects of Book model. You should either save the object after initialization bk.save or use the create method instead of new.
bk = Book.new(:sn => real_sn,:name => book_name, :isbn=>isbn,
:price =>Random.rand(200..5000), :location=>location,
:category=>["商業","歷史","體育","政治"].sample, :author => author,
:sale_type => [:fix_priced, :normal, :promotion].sample,
:publisher => publisher, :release_date => rand(10.years).ago,
:comment => comment)
bk.save
Or alternatively you can use the create method
bk = Book.create(:sn => real_sn,:name => book_name, :isbn=>isbn,
:price =>Random.rand(200..5000), :location=>location,
:category=>["商業","歷史","體育","政治"].sample, :author => author,
:sale_type => [:fix_priced, :normal, :promotion].sample,
:publisher => publisher, :release_date => rand(10.years).ago,
:comment => comment)
Once saved in the database, it will automatically gain a unique id.
I have 2 objects, Area and SurfBreak. Area has many SurfBreaks and a SurfBreak publishes its conditions based on wind,wave,tide info from Area. This bit I've done an it works well:-)
I now have list of forecast data for Area - future changes to Area's attributes.
Whats the best OOP method to show the Surfbreaks conditions using forecast data for Area ?
Many thanks
Andy
----Updated---
Its a rails app
class Spot < ActiveRecord::Base
belongs_to :area
has_many :forecasts, :through => :area
def has_swell
wind = "#{area.swelldir}"
beachstart = "#{breakstr}"
beachend = "#{breakend}"
if ( ((wind.to_i) + 360 - (beachstart.to_i)) % 360 <= ((beachend.to_i) + 360 - (beachstart.to_i)) % 360 )
"#{area.swelldir} Has Incoming swell "
else
"#{area.swelldir} No Swell"
end
end
class Area < ActiveRecord::Base
has_many :spots
has_many :forecasts
class Forecast < ActiveRecord::Base
belongs_to :area
The DB tables are the objects in rails. I've got Area and Spot working nicely but I now want to display forecasts for a spot. This is the bit I'm not sure about.
mysql> desc areas;
+----------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------+--------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| name | varchar(255) | NO | | NULL | |
| descrip | varchar(255) | YES | | NULL | |
| winddir | int(11) | NO | | NULL | |
| windspd | int(11) | NO | | NULL | |
| swelldir | int(11) | NO | | NULL | |
| swellhgt | float | NO | | NULL | |
| tide | int(11) | NO | | NULL | |
| lat | float | YES | | NULL | |
| lng | float | YES | | NULL | |
+----------+--------------+------+-----+---------+----------------+
10 rows in set (0.00 sec)
mysql> desc spots;
+----------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------+--------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| name | varchar(255) | NO | | NULL | |
| descrip | varchar(255) | NO | | NULL | |
| breakstr | int(11) | NO | | NULL | |
| breakend | int(11) | NO | | NULL | |
| offstr | int(11) | NO | | NULL | |
| offend | int(11) | NO | | NULL | |
| besttide | int(11) | NO | | NULL | |
| area_id | int(11) | NO | | NULL | |
+----------+--------------+------+-----+---------+----------------+
9 rows in set (0.00 sec)
mysql> desc forecasts;
+--------------+----------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+--------------+----------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| forecastdate | datetime | YES | | NULL | |
| area_id | int(11) | NO | | NULL | |
| winddir | int(11) | NO | | NULL | |
| windspd | int(11) | NO | | NULL | |
| swelldir | int(11) | NO | | NULL | |
| swellhgt | float | NO | | NULL | |
| tide | int(11) | NO | | NULL | |
+--------------+----------+------+-----+---------+----------------+
8 rows in set (0.00 sec)
So say an Area has 24 Forecast rows in a DB , one for every hour in the future. In my app
what is the best way to output a spots forecast conditions. Without changing the relevant values in the Area as Areas hold the current conditions. I could just pull all the forecast data into an array an loop through it changing the Area object data, but this doesn't seem very OOP to me ?
As output I'm after something like
Current Spot Details (Using spot methods on Area attributes)
xxx
Forecast Details for this spot (Using spot methods on Forecast attributes )
Hour 1 xxx
Hour 2 xxx
Hour 3 xxx
..
Sorry if this is not very well explained.
Regards
Andy
Your class Area sounds like it is doing too many things, and it is changing for different reasons. Separate it out so the Area has a list of WeatherData or something, so your forecasting code can iterate through the WeatherData without Area having to change. Your WeatherData object can include a flag saying whether it's real data or a forecast.
Class Area{
Wind wind;
Wave wave;
Tide tide;
}
Class SurfBreak extends Area{
//some SurfBreaks' field
public ForecastDetail getForecastDetail(){
//operate directly onwind wave tide fields and calculate
}
}
You haven't explained exactly how you developed first part of the problem (relations between Area and SurfBreaks), but, I would consider using of Observer design pattern here. So SurfBreaks would be Observers of Area changes.
I'm using rails 3 and I can't seem to check if a given instance is in a scope, see here:
p = Post.find 6
+----+----------+-------------------------+-------------------------+-------------------------+-----------+
| id | title | publish_date | created_at | updated_at | published |
+----+----------+-------------------------+-------------------------+-------------------------+-----------+
| 6 | asfdfdsa | 2010-03-28 22:33:00 UTC | 2010-03-28 22:33:46 UTC | 2010-03-28 22:33:46 UTC | true |
+----+----------+-------------------------+-------------------------+-------------------------+-----------+
I have a menu scope which looks like:
scope :menu, where("published != ?", false).limit(4)
When I run it I get:
Post.menu.all
+----+------------------+------------------+------------------+-------------------+-----------+
| id | title | publish_date | created_at | updated_at | published |
+----+------------------+------------------+------------------+-------------------+-----------+
| 1 | Lorem ipsum | 2010-03-23 07... | 2010-03-23 07... | 2010-03-28 21:... | true |
| 2 | fdasf | 2010-03-28 21... | 2010-03-28 21... | 2010-03-28 21:... | true |
| 3 | Ruby’s Imple... | 2010-03-28 21... | 2010-03-28 21... | 2010-03-28 21:... | true |
| 4 | dsaD | 2010-03-28 22... | 2010-03-28 22... | 2010-03-28 22:... | true |
+----+------------------+------------------+------------------+-------------------+-----------+
Which is correct, but if I try to check if p is in the the menu scope using: Post.menu.exists?(p) I get true when it should be false
What is the proper way to find out if a given instance of something is in a scope?
Actually, I was able to solve it using that Array method of include? instead of exists?
I have complex form similar to a recent Ryan Bates screencast
The nested elements work fine however. I'm creating or updating a grid of data such as this through a form where the day's prices are the input. My problem begins when they leave one blank. I have the nested_attributes_for option for not saving nils and it works, if they only save one value in a particular row, it saves the correct day however when reloaded, it will place it in the wrong column. I'm not sure how to order the values in a row to the form. IE A saved value for wednesday will appear in the monday column (of the correct row). This doesn't happen if they save all value for a row (then it works perfectly).
Data is stored in the DB like so
ID OBJECT_ID DAYOFWEEK PRICE and displaying like below
+------+----------------+-------+-------+-------+------+-------+
| id | name | Mon | Tue | Wed | Thu | Fri | -> +2 more days etc
+------+----------------+-------+-------+-------+------+-------+
| 1234 | Some name | 87.20 | 87.20 | 87.20 | 82.55| 85.48 |
+------+----------------+-------+-------+-------+------+-------+
| 1234 | Some name | 87.20 | 87.20 | 87.20 | 82.55| 85.48 |
+------+----------------+-------+-------+-------+------+-------+
| 1234 | Some name | 87.20 | 87.20 | 87.20 | 82.55| 85.48 |
+------+----------------+-------+-------+-------+------+-------+
The controller code either building or display these values is like so:
controller
#rooms.each do |r|
((r.room_rates.size+1)..7).each {
r.room_rates.build
}
end
rooms.html.erb
<% #dow = 0 %>
<tr class="room">
<td><%= f.text_field :name %></td>
<% f.fields_for :room_rates do |rates| %>
<%= render 'rates', :f => rates %>
<% #dow += 1 %>
<% end %>
<td class="delete_mode" style="display:none;">
<%= f.hidden_field :_destroy %>
<%= link_to_function "remove", "remove_room(this)" %>
</td>
</tr>
rates.html.erb
<td>
<%= f.text_field :price, :size => 3 %>
<%= f.hidden_field :dayofweek, :value => #dow %>
<%= f.hidden_field :source, :value => 0 %>
</td>
room_rates model (where the data from the form is going)
+-------+---------+-----------+-------+--------+---------------------------+---------------------------+
| id | room_id | dayofweek | price | source | created_at | updated_at |
+-------+---------+-----------+-------+--------+---------------------------+---------------------------+
| 92745 | 8 | 0 | 1.0 | 0 | 2010-02-23 14:33:05 +0100 | 2010-02-23 14:33:05 +0100 |
| 92746 | 8 | 1 | 2.0 | 0 | 2010-02-23 14:33:05 +0100 | 2010-02-23 14:33:05 +0100 |
| 92747 | 8 | 2 | 3.0 | 0 | 2010-02-23 14:33:05 +0100 | 2010-02-23 14:33:05 +0100 |
| 92748 | 8 | 3 | 4.0 | 0 | 2010-02-23 14:33:05 +0100 | 2010-02-23 14:33:05 +0100 |
| 92749 | 8 | 4 | 5.0 | 0 | 2010-02-23 14:33:05 +0100 | 2010-02-23 14:33:05 +0100 |
| 92750 | 8 | 5 | 6.0 | 0 | 2010-02-23 14:33:05 +0100 | 2010-02-23 14:33:05 +0100 |
| 92751 | 8 | 6 | 7.0 | 0 | 2010-02-23 14:33:05 +0100 | 2010-02-23 14:33:05 +0100 |
| 92752 | 9 | 3 | 5.0 | 0 | 2010-02-23 14:33:33 +0100 | 2010-02-23 14:33:33 +0100 |
+-------+---------+-----------+-------+--------+---------------------------+---------------------------+
ordering in the console
+---------+-----------+-------+--------+---------------------------+---------------------------+
| room_id | dayofweek | price | source | created_at | updated_at |
+---------+-----------+-------+--------+---------------------------+---------------------------+
| 2517 | 0 | | | | |
| 2517 | 1 | | | | |
| 2517 | 2 | 3.0 | 0 | 2010-02-23 17:54:28 +0100 | 2010-02-23 17:54:28 +0100 |
| 2517 | 3 | 4.0 | 0 | 2010-02-23 17:54:28 +0100 | 2010-02-23 17:54:28 +0100 |
| 2517 | 4 | | | | |
| 2517 | 5 | | | | |
| 2517 | 6 | | | | |
+---------+-----------+-------+--------+---------------------------+---------------------------+
The error is when you create the form - because you are depending on the order of the room_rates to be correct, you need to put the empty (built) rates into the correct positions. If each room has many room rates, you need to generate the form so that the rates are at the right day in the week. This code will build that in a new array, and set the new array correctly:
#rooms.each do |r|
new_rates = []
(0..6).each { |dow|
rate = r.room_rates.find_by_dayofweek(dow)
if rate
new_rates << rate
else
new_rates << r.room_rates.build(:dayofweek => dow)
end
}
r.room_rates = new_rates
end
Alternatively, you may be able to just build the missing weeks, if you specify an order for your association:
// In room model
has_many :rates, :order => "dayofweek"
// In controller
#rooms.each do |r|
(0..6).each { |dow|
if not r.room_rates.find_by_dayofweek(dow)
r.room_rates.build(:dayofweek => dow)
end
}
end