Module Sequel::Model::DatasetMethods
In: lib/sequel/model/base.rb

Dataset methods are methods that the model class extends its dataset with in the call to set_dataset.

Methods

[]   destroy   to_hash   with_pk  

Attributes

model  [RW]  The model class associated with this dataset 
  Artist.dataset.model # => Artist

Public Instance methods

[](*args)

Assume if a single integer is given that it is a lookup by primary key, and call with_pk with the argument. 

  Artist.dataset[1] # SELECT * FROM artists WHERE (id = 1) LIMIT 1

[Source]

      # File lib/sequel/model/base.rb, line 1562
1562:       def [](*args)
1563:         if args.length == 1 && (i = args.at(0)) && i.is_a?(Integer)
1564:           with_pk(i)
1565:         else
1566:           super
1567:         end
1568:       end
destroy()

Destroy each row in the dataset by instantiating it and then calling destroy on the resulting model object. This isn‘t as fast as deleting the dataset, which does a single SQL call, but this runs any destroy hooks on each object in the dataset. 

  Artist.dataset.destroy
  # DELETE FROM artists WHERE (id = 1)
  # DELETE FROM artists WHERE (id = 2)
  # ...

[Source]

      # File lib/sequel/model/base.rb, line 1579
1579:       def destroy
1580:         pr = proc{all{|r| r.destroy}.length}
1581:         model.use_transactions ? @db.transaction(&pr) : pr.call
1582:       end
to_hash(key_column=nil, value_column=nil)

This allows you to call to_hash without any arguments, which will result in a hash with the primary key value being the key and the model object being the value. 

  Artist.dataset.to_hash # SELECT * FROM artists
  # => {1=>#<Artist {:id=>1, ...}>,
  #     2=>#<Artist {:id=>2, ...}>,
  #     ...}

[Source]

      # File lib/sequel/model/base.rb, line 1592
1592:       def to_hash(key_column=nil, value_column=nil)
1593:         if key_column
1594:           super
1595:         else
1596:           raise(Sequel::Error, "No primary key for model") unless model and pk = model.primary_key
1597:           super(pk, value_column) 
1598:         end
1599:       end
with_pk(pk)

Given a primary key value, return the first record in the dataset with that primary key value. 

  # Single primary key
  Artist.dataset.with_pk(1) # SELECT * FROM artists WHERE (id = 1) LIMIT 1

  # Composite primary key
  Artist.dataset.with_pk([1, 2]) # SELECT * FROM artists
                                 # WHERE ((id1 = 1) AND (id2 = 2)) LIMIT 1

[Source]

      # File lib/sequel/model/base.rb, line 1610
1610:       def with_pk(pk)
1611:         case primary_key = model.primary_key
1612:         when Array
1613:           raise(Error, "single primary key given (#{pk.inspect}) when a composite primary key is expected (#{primary_key.inspect})") unless pk.is_a?(Array)
1614:           raise(Error, "composite primary key given (#{pk.inspect}) does not match composite primary key length (#{primary_key.inspect})") if pk.length != primary_key.length
1615:           first(primary_key.zip(pk))
1616:         else
1617:           raise(Error, "composite primary key given (#{pk.inspect}) when a single primary key is expected (#{primary_key.inspect})") if pk.is_a?(Array)
1618:           first(primary_key=>pk)
1619:         end
1620:       end

[Validate]