relation

I see the juxtaposition of these two errors and, given the dearth of Google search results, had to ask. What is the difference and what do I need to be doing here? deploy=# GRANT SELECT ON angel_research_production TO angel_research; ERROR: relation "angel_research_production" does not exist deploy=# create database angel_research_production; ERROR: database "angel_research_production" already exists My guess is that I need to be doing this grant select business from some other user... So I run this on postgres (dbroot) and get this: postgres=# GRANT SELECT ON angel_research_production TO

For my application I need to represent simultaneously (on the same graph) two relations: one is simmetric, the other is not. Targets: Ideally the two relation should result in edges having different colors; For the symmetric relation I would like not to have double-edges; Is there a way of doing this with dot ? digraph { A; B; C subgraph Rel1 { edge [dir=none, color=red] A -> B -> C -> A } subgraph Rel2 { edge [color=blue] B -> C C -> A } } 来源： https://stackoverflow.com/questions/13236975/graphviz-dot-mix-directed-and-undirected

I've a relation on a pivot table; how I can expand It? For example: shops : id name products : id name product_shop : product_id shop_id field_1 field_2 field_3 table_A_id table_A : id name The relation Many-to-Many in the Shops Model is: class Shops extends Model { public function products() { return $this->belongsToMany('Products', 'product_shop', 'product_id', 'shop_id')->withPivot( 'field_1', 'field_3', 'field_3', 'table_A_id' ) ->as('product_shop') ->withTimestamps(); } } and the query to retrieve all data is: class GetData extends Model { public static function getAll() { $query = Shops:

How can I group by relation? Example Sales::with('product_detail.product')->groupBy('product_name')->get() How can I get a result with eloquent code? Imtiaz Pabel You can specify a callback function for grouping your relation like this: Sales::with(['product_detail.product' => function($query){ $query->groupBy('product_name'); }])->get(); this will help you to do grouping by relation. $sales = Order::Sales('product') ->where('approved','=','Yes') ->groupBy('product_id') ->orderBy(DB::raw('COUNT(id)','desc')) ->get(array(DB::raw('COUNT(id) as totalsales'),'product_id')); 来源： https:/

Say I have two relations that hold records in the same model, such as: @companies1 = Company.where(...) @companies2 = Company.where(...) How can I find the intersection of these two relations, i.e. only those companies that exist within both? By default connecting those where together creates AND which is what you want. So many be: class Company < ActiveRecord::Base def self.where_1 where(...) end def self.where_2 where(...) end end @companies = Company.where_1.where_2 ====== UPDATED ====== There are two cases: # case 1: the fields selecting are different Company.where(:id => [1, 2, 3, 4]) &

I am developing an iPhone application that has support for video play. I am using MPMoviePlayerController with custom controls for playing the video. For this purpose I have set control style of MPMoviePlayerController to MPMovieControlStyleNone. I would like to support AirPlay feature for the video being played. As per the documentation, we have to set the 'allowsAirPlay' property of MPMoviePlayerController to YES to enable AirPlay feature. How can I display the AirPlay button on my player UI if I am using MPMoviePlayerController with custom controls? I have tried the following: Instantiated

If I have a scope with a lambda and it takes an argument, depending on the value of the argument, I might know that there will not be any matches, but I still want to return a relation, not an empty array: scope :for_users, lambda { |users| users.any? ? where("user_id IN (?)", users.map(&:id).join(',')) : [] } What I really want is a "none" method, the opposite of "all", that returns a relation that can still be chained, but results in the query being short-circuited. steveh7 There is a now a "correct" mechanism in Rails 4: >> Model.none => #<ActiveRecord::Relation []> A more portable solution