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
2125 def [](*args)
2126   if args.length == 1 && (i = args[0]) && i.is_a?(Integer)
2127     with_pk(i)
2128   else
2129     super
2130   end
2131 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
2184 def as_hash(key_column=nil, value_column=nil, opts=OPTS)
2185   if key_column
2186     super
2187   else
2188     raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key)
2189     super(pk, value_column, opts) 
2190   end
2191 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
2142 def destroy
2143   pr = proc{all(&:destroy).length}
2144   model.use_transactions ? @db.transaction(:server=>opts[:server], &pr) : pr.call
2145 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
2152 def last(*a, &block)
2153   if ds = _primary_key_order
2154     ds.last(*a, &block)
2155   else
2156     super
2157   end
2158 end
model()

The model class associated with this dataset

Artist.dataset.model # => Artist
[show source]
     # File lib/sequel/model/base.rb
2117 def model
2118   @opts[:model]
2119 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
2168 def paged_each(*a, &block)
2169   if ds = _primary_key_order
2170     ds.paged_each(*a, &block)
2171   else
2172     super
2173   end
2174 end
to_hash(*a)

Alias of as_hash for backwards compatibility.

[show source]
     # File lib/sequel/model/base.rb
2194 def to_hash(*a)
2195   as_hash(*a)
2196 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
2208 def with_pk(pk)
2209   if pk && (loader = _with_pk_loader)
2210     loader.first(*pk)
2211   else
2212     first(model.qualified_primary_key_hash(pk))
2213   end
2214 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
2218 def with_pk!(pk)
2219   with_pk(pk) || raise(NoMatchingRow.new(self))
2220 end