module Sequel::Model::DatasetMethods

  1. lib/sequel/model/base.rb

DatasetMethods contains methods that all model datasets have.

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
[show source]
     # File lib/sequel/model/base.rb
2131 def [](*args)
2132   if args.length == 1 && (i = args[0]) && i.is_a?(Integer)
2133     with_pk(i)
2134   else
2135     super
2136   end
2137 end
as_hash(key_column=nil, value_column=nil, opts=OPTS)

This allows you to call as_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.as_hash # SELECT * FROM artists
# => {1=>#<Artist {:id=>1, ...}>,
#     2=>#<Artist {:id=>2, ...}>,
#     ...}
[show source]
     # File lib/sequel/model/base.rb
2190 def as_hash(key_column=nil, value_column=nil, opts=OPTS)
2191   if key_column
2192     super
2193   else
2194     raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key)
2195     super(pk, value_column, opts) 
2196   end
2197 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)
# ...
[show source]
     # File lib/sequel/model/base.rb
2148 def destroy
2149   pr = proc{all(&:destroy).length}
2150   model.use_transactions ? @db.transaction(:server=>opts[:server], &pr) : pr.call
2151 end
last(*a, &block)

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
[show source]
     # File lib/sequel/model/base.rb
2158 def last(*a, &block)
2159   if ds = _primary_key_order
2160     ds.last(*a, &block)
2161   else
2162     super
2163   end
2164 end
model()

The model class associated with this dataset

Artist.dataset.model # => Artist
[show source]
     # File lib/sequel/model/base.rb
2123 def model
2124   @opts[:model]
2125 end
paged_each(*a, &block)

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
# ...
[show source]
     # File lib/sequel/model/base.rb
2174 def paged_each(*a, &block)
2175   if ds = _primary_key_order
2176     ds.paged_each(*a, &block)
2177   else
2178     super
2179   end
2180 end
to_hash(*a)

Alias of as_hash for backwards compatibility.

[show source]
     # File lib/sequel/model/base.rb
2200 def to_hash(*a)
2201   as_hash(*a)
2202 end
with_pk(pk)

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 (artists.id = 1) LIMIT 1

# Composite primary key
Artist.dataset.with_pk([1, 2])
# SELECT * FROM artists WHERE ((artists.id1 = 1) AND (artists.id2 = 2)) LIMIT 1
[show source]
     # File lib/sequel/model/base.rb
2214 def with_pk(pk)
2215   if pk && (loader = _with_pk_loader)
2216     loader.first(*pk)
2217   else
2218     first(model.qualified_primary_key_hash(pk))
2219   end
2220 end
with_pk!(pk)

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

[show source]
     # File lib/sequel/model/base.rb
2224 def with_pk!(pk)
2225   with_pk(pk) || raise(NoMatchingRow.new(self))
2226 end