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   graph   insert_sql   join_table   last   paged_each   to_hash   with_pk   with_pk!  

Attributes

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

Public Instance methods

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 1902
1902:       def [](*args)
1903:         if args.length == 1 && (i = args.at(0)) && i.is_a?(Integer)
1904:           with_pk(i)
1905:         else
1906:           super
1907:         end
1908:       end

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 1919
1919:       def destroy
1920:         pr = proc{all{|r| r.destroy}.length}
1921:         model.use_transactions ? @db.transaction(:server=>opts[:server], &pr) : pr.call
1922:       end

Allow Sequel::Model classes to be used as dataset arguments when graphing:

  Artist.graph(Album, :artist_id=>id)
  # SELECT artists.id, artists.name, albums.id AS albums_id, albums.artist_id, albums.name AS albums_name
  # FROM artists LEFT OUTER JOIN albums ON (albums.artist_id = artists.id)

[Source]

      # File lib/sequel/model/base.rb, line 1929
1929:       def graph(table, *args, &block)
1930:         if table.is_a?(Class) && table < Sequel::Model
1931:           super(table.dataset, *args, &block)
1932:         else
1933:           super
1934:         end
1935:       end

Handle Sequel::Model instances when inserting, using the model instance‘s values for the insert, unless the model instance can be used directly in SQL.

  Album.insert(Album.load(:name=>'A'))
  # INSERT INTO albums (name) VALUES ('A')

[Source]

      # File lib/sequel/model/base.rb, line 1943
1943:       def insert_sql(*values)
1944:         if values.size == 1 && (v = values.at(0)).is_a?(Sequel::Model) && !v.respond_to?(:sql_literal_append)
1945:           super(v.to_hash)
1946:         else
1947:           super
1948:         end
1949:       end

Allow Sequel::Model classes to be used as table name arguments in dataset join methods:

  Artist.join(Album, :artist_id=>id)
  # SELECT * FROM artists INNER JOIN albums ON (albums.artist_id = artists.id)

[Source]

      # File lib/sequel/model/base.rb, line 1956
1956:       def join_table(type, table, *args, &block)
1957:         if table.is_a?(Class) && table < Sequel::Model
1958:           if table.dataset.simple_select_all?
1959:             super(type, table.table_name, *args, &block)
1960:           else
1961:             super(type, table.dataset, *args, &block)
1962:           end
1963:         else
1964:           super
1965:         end
1966:       end

If there is no order already defined on this dataset, order it by the primary key and call last.

  Album.last
  # SELECT * FROM albums ORDER BY id DESC LIMIT 1

[Source]

      # File lib/sequel/model/base.rb, line 1973
1973:       def last(*a, &block)
1974:         if opts[:order].nil? && model && (pk = model.primary_key)
1975:           order(*pk).last(*a, &block)
1976:         else
1977:           super
1978:         end
1979:       end

If there is no order already defined on this dataset, order it by the primary key and call paged_each.

  Album.paged_each{|row| ...}
  # SELECT * FROM albums ORDER BY id LIMIT 1000 OFFSET 0
  # SELECT * FROM albums ORDER BY id LIMIT 1000 OFFSET 1000
  # SELECT * FROM albums ORDER BY id LIMIT 1000 OFFSET 2000
  # ...

[Source]

      # File lib/sequel/model/base.rb, line 1989
1989:       def paged_each(*a, &block)
1990:         if opts[:order].nil? && model && (pk = model.primary_key)
1991:           order(*pk).paged_each(*a, &block)
1992:         else
1993:           super
1994:         end
1995:       end

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 2005
2005:       def to_hash(key_column=nil, value_column=nil)
2006:         if key_column
2007:           super
2008:         else
2009:           raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key)
2010:           super(pk, value_column) 
2011:         end
2012:       end

Given a primary key value, return the first record in the dataset with that primary key value. If no records matches, returns nil.

  # 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 2023
2023:       def with_pk(pk)
2024:         first(model.qualified_primary_key_hash(pk))
2025:       end

Same as with_pk, but raises NoMatchingRow instead of returning nil if no row matches.

[Source]

      # File lib/sequel/model/base.rb, line 2029
2029:       def with_pk!(pk)
2030:         with_pk(pk) || raise(NoMatchingRow)
2031:       end

[Validate]