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
2132 def [](*args)
2133   if args.length == 1 && (i = args[0]) && i.is_a?(Integer)
2134     with_pk(i)
2135   else
2136     super
2137   end
2138 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
2191 def as_hash(key_column=nil, value_column=nil, opts=OPTS)
2192   if key_column
2193     super
2194   else
2195     raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key)
2196     super(pk, value_column, opts) 
2197   end
2198 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
2149 def destroy
2150   pr = proc{all(&:destroy).length}
2151   model.use_transactions ? @db.transaction(:server=>opts[:server], &pr) : pr.call
2152 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
2159 def last(*a, &block)
2160   if ds = _primary_key_order
2161     ds.last(*a, &block)
2162   else
2163     super
2164   end
2165 end
model()

The model class associated with this dataset

Artist.dataset.model # => Artist
[show source]
     # File lib/sequel/model/base.rb
2124 def model
2125   @opts[:model]
2126 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
2175 def paged_each(*a, &block)
2176   if ds = _primary_key_order
2177     ds.paged_each(*a, &block)
2178   else
2179     super
2180   end
2181 end
to_hash(*a)

Alias of as_hash for backwards compatibility.

[show source]
     # File lib/sequel/model/base.rb
2201 def to_hash(*a)
2202   as_hash(*a)
2203 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
2215 def with_pk(pk)
2216   if pk && (loader = _with_pk_loader)
2217     loader.first(*pk)
2218   else
2219     first(model.qualified_primary_key_hash(pk))
2220   end
2221 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
2225 def with_pk!(pk)
2226   with_pk(pk) || raise(NoMatchingRow.new(self))
2227 end