activerecord

问题 Please notice, this is not a question about adding a WHERE condition to an association but a rather advanced question about how to alter the JOIN clause when using eager_load. Lets say I have these models class Parent has_many :children have_many :grades, through: :children end class Child belongs_to :parent end class Grade belongs_to :child end So to eager load the parents I would do: Parent.eager_load(:grades) But if I wanted all the parents - but only to eager load the highest scoring like

问题 I'm having a problem converting below MySQL code to a Codeigniter active record query. SELECT sss.*, c.country_name, c.country_code FROM ( SELECT gr.* FROM (`be_goldrate` as `gr`) WHERE `gr`.`country_id` != 0 AND `gr`.`rate_type` = 'calculated' ORDER BY gr.date DESC ) as sss LEFT JOIN `be_countries` as `c` ON `c`.`country_id`=`sss`.`country_id` GROUP BY `sss`.`country_id` I've tried as suggested here but without success. 回答1: you just need to check the Codeigniter Documentation $this->db-

问题 When in "edit" or "show" this comes up: ActiveRecord::SubclassNotFound in Registries#edit "The single-table inheritance mechanism failed to locate the subclass: 'Plane'. This error is raised because the column 'type' is reserved for storing the class in case of inheritance. Please rename this column if you didn't intend it to be used for storing the inheritance class or overwrite Present.inheritance_column to use another column for that information." 25: </div> 26: 27: <div class="field1"> 28

问题 When in "edit" or "show" this comes up: ActiveRecord::SubclassNotFound in Registries#edit "The single-table inheritance mechanism failed to locate the subclass: 'Plane'. This error is raised because the column 'type' is reserved for storing the class in case of inheritance. Please rename this column if you didn't intend it to be used for storing the inheritance class or overwrite Present.inheritance_column to use another column for that information." 25: </div> 26: 27: <div class="field1"> 28

问题 rake db:create showing error PG::InvalidParameterValue: ERROR: invalid value for parameter "client_min_messages": "panic" HINT: Available values: debug5, debug4, debug3, debug2, debug1, log, notice, warning, error. After bundle install tried to run rake db:create commond. Created database.yml file inside the config folder please find below : development: adapter: postgresql encoding: utf8 database: thor_development1 username: postgres password: host: localhost test: adapter: postgresql

问题 I am working on a testing framework for the software that my company writes. Our product is web based and After I run a RESTful request I want to process the results. I want to be able to have activerecord type validations in each command class so that after it is run the results are automatically tested against all the "validations". However, I am not sure how to do this. My code looks like this (simplified to show the important parts). class CodesecureCommand def execute result = RestClient

问题 I read through the API for Active Record Querying, but it doesn't seem to include a method for the user to actually input search data. I assume I could somehow link_to a method which contains the query code, but how could I use specific search params? Let's say I only want to search by name for matching instances of one model. Thanks in advance! 回答1: the simple way to do it is Model.find(:all, :conditions => ['name LIKE ?', "%#{search}%"]) in View <% form_tag projects_path, :method => 'get'

问题 In Rails, I have created a Model that retrieves users from an LDAP database rather than from ActiveRecord. Now I am attempting to integrate my ActiveRecord models with the LDAP-based models, so I am writing methods in my models that emulate some common ActiveRecord methods. One of the methods I am trying to emulate is one that is normally created by the has_many through relationship on ActiveRecord. In ActiveRecord, this relationship would allow the following: user = User.first groups = user

问题 OK I'm banging my head against a wall with this one ;-) Given tables in my database called Address, Customer and CustomerType, I want to display combined summary information about the customer so I create a query to join these two tables and retrieve a specified result. var customers = (from c in tblCustomer.All() join address in tblAddress.All() on c.Address equals address.AddressId join type in tblCustomerType.All() on c.CustomerType equals type.CustomerTypeId select new CustomerSummaryView

问题 I'm developing a Rails 3 application (with MySQL as RDMS) to manage availability/occupancy for some Rooms (it's an hotel-like app) In my case, the problem is I've to keep up in the system 2 different requirements because one room can be rented for: Some months (for example 6 monts) Some days/weeks/weekend Clearly the app has to show for each room in a given date, if it is available or not, and which user is renting; and on the other side, one user can search one room for a given date range.