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
2135 def [](*args)
2136   if args.length == 1 && (i = args[0]) && i.is_a?(Integer)
2137     with_pk(i)
2138   else
2139     super
2140   end
2141 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
2195 def as_hash(key_column=nil, value_column=nil, opts=OPTS)
2196   if key_column
2197     super
2198   else
2199     raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key)
2200     super(pk, value_column, opts) 
2201   end
2202 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
2152 def destroy
2153   @db.transaction(:server=>opts[:server], :skip_transaction=>model.use_transactions == false) do
2154     all(&:destroy).length
2155   end
2156 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
2163 def last(*a, &block)
2164   if ds = _primary_key_order
2165     ds.last(*a, &block)
2166   else
2167     super
2168   end
2169 end
model()

The model class associated with this dataset

Artist.dataset.model # => Artist
[show source]
     # File lib/sequel/model/base.rb
2127 def model
2128   @opts[:model]
2129 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
2179 def paged_each(*a, &block)
2180   if ds = _primary_key_order
2181     ds.paged_each(*a, &block)
2182   else
2183     super
2184   end
2185 end
to_hash(*a)

Alias of as_hash for backwards compatibility.

[show source]
     # File lib/sequel/model/base.rb
2205 def to_hash(*a)
2206   as_hash(*a)
2207 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
2219 def with_pk(pk)
2220   if pk && (loader = _with_pk_loader)
2221     loader.first(*pk)
2222   else
2223     first(model.qualified_primary_key_hash(pk))
2224   end
2225 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
2229 def with_pk!(pk)
2230   with_pk(pk) || raise(NoMatchingRow.new(self))
2231 end