Ruby on Rails

On 26 February 2013 11:47, Sajeev Zacharias <sajeev.zacharias4@gmail.com> wrote:
> I have 3 models,
>
> class Host
> ref: string
> address: string,
> name: string
> primary_key='ref'
> has_many :rooms, :class_name=>"Room", :foreign_key=>'host_ref'
>
> Class Room
> ref :string
> host_ref: string
> capacity: integer
> primary_key='ref'
> has_many :bookings, :class_name=>"Booking",
> :foreign_key=>'room_ref'
> belongs_to :host

You will need a foreign_key spec on the above.

>
> Class Booking
> ref: string
> room_ref :string
> start_date: date
> end_date: string

Why is end_date a string?

> number_of_guests :integer
> primary_key='ref'
> belongs_to :room

You will need a foreign_key spec here also.


Unless you are connecting to a legacy database that you /definitely/
cannot change then do not use unusual names for the keys, and do not
use string types. With Rails your life will be much simpler if you
stick to the Rails conventions.

>
> Here one should be able to see the vacancies against each host.
> A person when he enters the start date, end date and number of persons to
> book for a room, he must get the list of hosts who have rooms vacant and
> number of vacancies. How can I write the query in rails?

If you cannot see how to write the complete query then, for a start,
just do what you can in the query and do the rest in code. Make sure
that your automated tests check out the results and the tests pass.
Then, if necessary, you can refactor the code and queries to make it
more efficient, secure in the knowledge that your tests will show that
it is correct. If you cannot even see how to make a start then the
first thing is to write the requirement in pseudo code (something like
find hosts where ..and ..). Once you can write that down clearly and
unambiguously then you should be well on the way towards the solution.

Colin

>
> for example:
>
> Suppose the records are
> Host
> ref name address
> host#1 Mr Allan 23, Camden Street
> host#2 Mr Tom 12, nassau Street
> host#3 Mr anice 34, Philip street
>
> Room
> ref host_ref capacity
> room#1 host#1 3
> room#2 host#2 1
> room#3 host#2 4
> room#4 host#3 2
> room#5 host#3 1
> room#6 host#3 2
> room#7 host#3 3
>
> Booking
> ref room_ref start_date end_date no_of_guests
> b#1 room#1 10-02-2013 20-02-2013 2
> b#2 room#2 05-02-2013 15-02-2013 1
> b#3 room#1 01-02-2013 13-02-2013 1
> b#4 room#3 15-02-2013 28-02-2013 1
> b#5 room#5 10-03-2013 15-03-2013 1
> b#6 room#7 15-02-2013 25-02-2013 1
>
>
> I want to search for the number of vacancies against each host.
> suppose I want to search as
>
> start date: 15-02-2013 end date:18-02-2013 number of persons:2
>
> I must get the result as:
>
> host#2 Mr Tom 12, nassau Street
> room#3 1 booked 3 free 4 total
>
> host#3 Mr anice 34, Philip street
> room#4 0 booked 2 free 2 total
> room#6 0 booked 2 free 2 total
> room#7 1 booked 2 free 3 total
>
> Example 2: If I want to search as
>
> start date: 01-02-2013 end date 13-02-2013 no of persons:1
>
> I must get the result as
>
> host#1 Mr Allan 23, Camden Street
> room#1 2 booked 1 free 3 total
>
> host#2 Mr Tom 12, nassau Street
> room#2 0 booked 1 free 1 total
>
> host#3
> room#4 0 booked 2 free 2 total
> room#5 0 booked 1 free 1 total
> room#6 0 booked 2 free 2 total
> room#7 1 booked 2 free 3 total
> How can I achieve this result in rails? Can I get the query for this or
> loop?
>
> --
> You received this message because you are subscribed to the Google Groups
> "Ruby on Rails: Talk" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to rubyonrails-talk+unsubscribe@googlegroups.com.
> To post to this group, send email to rubyonrails-talk@googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msg/rubyonrails-talk/-/YMbxBYzIiKsJ.
> For more options, visit https://groups.google.com/groups/opt_out.
>
>

--
You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group.
To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscribe@googlegroups.com.
To post to this group, send email to rubyonrails-talk@googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.