如何我插入一個數組使用ActiveRecord一個PostgreSQL表？

Question

我active_record設置爲使用PostgreSQL數據庫。其中一列是character varying[]（基本上是VARCHAR數組）。

無論如何，我的導入例程然後讀取製表符分隔的文本文件，並插入記錄。一切都很好，直到我得到一個數組。應該轉換爲數組的列以逗號分隔。但該行本身是製表符分隔的。

我導入看起來像數據的樣品（製表符分隔）：

Col1  Col2  Col3     Col4 
---------------------------------------------- 
Apple  Pear  Sweet,Round,Green  Fruit 

COL3導入等（紅寶石）：col3.split(/,/)這使我在紅寶石陣列。但active_record彈出：

PG::Error: ERROR: array value must start with "{" or dimension information (ActiveRecord::StatementInvalid)

如何正確插入該列？
此外，有時，COL3將是NULL。

Answer 1

我可以使用下面的Ruby代碼中插入：

alternatenames = '{' + s[3].split(/,/).map {|n| '"' + n + '"'}.join(",") + '}' 

Answer 2

檢查Postgres的這個文檔：http://www.postgresql.org/docs/9.2/static/arrays.html

可以使用像數組實例化一個模型[：我，：符號]或[「我的」，「字符串」]，但它（在我的經驗，並形成什麼，似乎在docs）將保存元素的字符串。

Search.create(tokens: [{hash: 'value'}, {test: "fails"}]) 
=> TypeError: can't cast Hash to string 

凡爲：

[15] pry(main)> Search.create(tokens: [:G, :F]) 
=> #<Search id: 78, tokens: [:G, :F], created_at: "2013-12-18 06:29:36", updated_at: "2013-12-18 06:29:36"> 
[16] pry(main)> Search.last 
=> #<Search id: 78, tokens: ["G", "F"], created_at: "2013-12-18 06:29:36", updated_at: "2013-12-18 06:29:36"> 

在我的測試中，我有一個的搜索引擎，搜索和期限。

class SearchEngine < ActiveRecord::Base 
    has_and_belongs_to_many :terms 
    has_many :searches, through: :terms 
end 

class Term < ActiveRecord::Base 
    has_and_belongs_to_many :searches 
    has_and_belongs_to_many :searche_engines 
end 

class Search < ActiveRecord::Base 
    has_many :rankings 
    has_many :results, through: :rankings 
    has_and_belongs_to_many :terms 
    has_many :search_engines, through :terms 
end 


# These work: 
# these next two are the way postgrespl says to query against the array. You get the 
Search.where(tokens: '{A,B}') 
Search.where(tokens: '{C,D}').first_or_create 

[3] pry(main)> Search.where(tokens: ['C','D']).first 
ActiveRecord::StatementInvalid: PG::InvalidTextRepresentation: ERROR: array value must start with "{" or dimension information 

[4] pry(main)> Search.where(tokens: '{C,D}').first 
=> #<Search id: 77, tokens: ["C", "D"], created_at: "2013-12-18 06:27:24", updated_at: "2013-12-18 06:27:24"> 

term = "accident" 
Search.where("? = ANY (tokens)", term).first 
=> #<Search id: 8, tokens: ["accident", "prevention", "safety"], created_at: "2013-12-18 07:48:13", updated_at: "2013-12-18 07:48:13"> 
Search.create(tokens: [:Aortic, :Any, :Other, :Elements]) 
Search.where("'Aortic' = ANY (tokens)").first 
Parent.first.first_relationships.first.second_.where("'smelly' = ANY (tokens)").first 
# The next one will create one with an empty array for tokens and push it into Term.searches anyway. Same thing with 'smelly' 
Term.first.searches.where("':smelly' = ANY (tokens)").first_or_create do |s| Term.first.searches << s 
end 

# These error 
Search.where(tokens: "Aortic").first 
Search.where(tokens: [:Aortic, :Any, :Other, :Elements]).first 

另外，如果您有嵌套數組，你可以做一個地方搜索與此：「{{1,2,3}，{4,5,6}，{7,8,9}} '查找具有列值的行[[1,2,3]，[4,5,6]，[7,8,9]]