On Thursday, September 26, 2019 at 5:03:00 PM UTC-4, Ariel Juodziukynas wrote: > > You were asking a way to store different values, I thought you wanted to > preserve the type (so you can distinguish 1 from "1" when you read the > record). > > If you think strings are enough for your requirements just use a string > column, if you want to use one column to store values but preserve the > original type you have to serialize the value somehow (that's the is_a?... > when serializing and the case when casting). > > Another option is to use two columns: one for the stringified value and > one for the original type so you can parse that again. > > El jue., 26 sept. 2019 a las 17:57, fugee ohu (<[email protected] > <javascript:>>) escribió: > >> >> >> On Thursday, September 26, 2019 at 4:32:10 PM UTC-4, Ariel Juodziukynas >> wrote: >>> >>> The easiest but too big is a text columns so you can use >>> activerecord' serialization of attributes to save anything you want on a >>> text field and activerecord will handle casting. >>> >>> You could use a string column if you know your values won't be too big >>> (VARCHAR(255)) and you know what types you want to accept and handle >>> serialization yourself like: >>> >>> def value=(something) >>> val = if value.is_a?(Integer) >>> "integer:#{something}" >>> elsif value.is_a?(String) >>> "string:#{something}" >>> elsif value.is_a?(Date) >>> "date:#{something} >>> # etc... >>> write_attribute(:value, val) >>> end >>> >>> def value >>> type, val = read_attribute(:value).split(':') >>> case type >>> when "integer" then val.to_i >>> when "string" then val >>> when "date" then Date.parse(val) >>> etc... >>> end >>> >>> >>> El jue., 26 sept. 2019 a las 17:17, fugee ohu (<[email protected]>) >>> escribió: >>> >>>> >>>> >>>> On Monday, September 16, 2019 at 4:31:29 PM UTC-4, Ariel Juodziukynas >>>> wrote: >>>>> >>>>> Personally, I would do this: >>>>> >>>>> auctions table >>>>> (with the basic shared information of all auctions and an "auction >>>>> type")) >>>>> >>>>> properties table >>>>> property_name (like network, carrier, publisher, etc) >>>>> auction_type (like cellphone, book, etc) >>>>> >>>>> auctions_properties >>>>> auction_id >>>>> property_id >>>>> value >>>>> >>>>> That way you can have any number of auction types with any number of >>>>> specific properties with just 3 tables. >>>>> >>>>> Note that the "value" column would be some string variation (VARCHAR, >>>>> CHAR, TEXT, etc) depending on your needs, maybe you want to redesign it a >>>>> little if you want to store different types. Like if you want to store an >>>>> integer (and retrieve an integer) you'll have to save the original type >>>>> and >>>>> reparse it (you could use serialization but that requires a TEXT column >>>>> and >>>>> maybe you can't use that many space) >>>>> >>>>> El lun., 16 sept. 2019 a las 17:19, fugee ohu (<[email protected]>) >>>>> escribió: >>>>> >>>>>> I was looking at some auction projects that use a single listings >>>>>> table for all auctions but I know on auction sites the form will be >>>>>> different for different types of items like if you're selling a cell >>>>>> phone >>>>>> there'll be a form field for network, carrier, whatever and if you're >>>>>> selling a book there'll be form fields for publisher, year of >>>>>> publication, >>>>>> so they would have separate tables I assume for books, cell phones, etc? >>>>>> Then how would they treat them all as one? >>>>>> >>>>>> -- >>>>>> 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 [email protected]. >>>>>> To view this discussion on the web visit >>>>>> https://groups.google.com/d/msgid/rubyonrails-talk/512f8b73-e3a4-4e74-95e7-4281e7b54821%40googlegroups.com >>>>>> >>>>>> <https://groups.google.com/d/msgid/rubyonrails-talk/512f8b73-e3a4-4e74-95e7-4281e7b54821%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>>> . >>>>>> >>>>> >>>> What data type do you suggest for value column >>>> >>>> -- >>>> 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 [email protected]. >>>> To view this discussion on the web visit >>>> https://groups.google.com/d/msgid/rubyonrails-talk/e74aaf6b-b9e1-4847-a6d3-3120829fa3bc%40googlegroups.com >>>> >>>> <https://groups.google.com/d/msgid/rubyonrails-talk/e74aaf6b-b9e1-4847-a6d3-3120829fa3bc%40googlegroups.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>> >> If I'm using a string column then whatever value is put in it is a >> string, so I don't understand all these "'if value.is_a?" conditions >> >> -- >> 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 [email protected] <javascript:>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/rubyonrails-talk/93726aa7-2667-4f3b-b27c-6d19d5e5f368%40googlegroups.com >> >> <https://groups.google.com/d/msgid/rubyonrails-talk/93726aa7-2667-4f3b-b27c-6d19d5e5f368%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > i=Item.first i.item_properties NameError: uninitialized constant Item::ItemProperties
class Item < ApplicationRecord has_many :boxes has_many :item_pictures has_many :pictures, through: :item_pictures has_many :item_item_properties, primary_key: 'item_type', foreign_key: 'item_type' has_many :item_properties, through: :item_item_properties ITEM_TYPES = ['General', 'Book', 'Record', 'Magazine', 'Pez dispenser', 'CD', 'VHS casette'] validates :item_type, inclusion: ITEM_TYPES attr_accessor "Year" end class ItemItemProperty < ApplicationRecord belongs_to :items, primary_key: 'item_type', foreign_key: 'item_type' belongs_to :item_properties, primary_key: 'item_type', foreign_key: 'item_type' end class ItemProperty < ApplicationRecord has_many :item_item_properties, primary_key: 'item_type', foreign_key: 'item_type' has_many :items, through: :item_item_properties end -- 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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/fb472c34-e7ab-4274-945d-03233a21e77c%40googlegroups.com.
