module Sequel::Model::DatasetMethods

DatasetMethods contains methods that all model datasets have.

Public Instance Methods

[](*args) click to toggle source

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
Calls superclass method
     # File lib/sequel/model/base.rb
2160 def [](*args)
2161   if args.length == 1 && (i = args[0]) && i.is_a?(Integer)
2162     with_pk(i)
2163   else
2164     super
2165   end
2166 end
as_hash(key_column=nil, value_column=nil, opts=OPTS) click to toggle source

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, ...}>,
#     ...}
Calls superclass method
     # File lib/sequel/model/base.rb
2220 def as_hash(key_column=nil, value_column=nil, opts=OPTS)
2221   if key_column
2222     super
2223   else
2224     raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key)
2225     super(pk, value_column, opts) 
2226   end
2227 end
destroy() click to toggle source

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)
# ...
     # File lib/sequel/model/base.rb
2177 def destroy
2178   @db.transaction(:server=>opts[:server], :skip_transaction=>model.use_transactions == false) do
2179     all(&:destroy).length
2180   end
2181 end
last(*a, &block) click to toggle source

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
Calls superclass method
     # File lib/sequel/model/base.rb
2188 def last(*a, &block)
2189   if ds = _primary_key_order
2190     ds.last(*a, &block)
2191   else
2192     super
2193   end
2194 end
model() click to toggle source

The model class associated with this dataset

Artist.dataset.model # => Artist
     # File lib/sequel/model/base.rb
2152 def model
2153   @opts[:model]
2154 end
paged_each(*a, &block) click to toggle source

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
# ...
Calls superclass method
     # File lib/sequel/model/base.rb
2204 def paged_each(*a, &block)
2205   if ds = _primary_key_order
2206     ds.paged_each(*a, &block)
2207   else
2208     super
2209   end
2210 end
to_hash(*a) click to toggle source

Alias of as_hash for backwards compatibility.

     # File lib/sequel/model/base.rb
2230 def to_hash(*a)
2231   as_hash(*a)
2232 end
with_pk(pk) click to toggle source

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
     # File lib/sequel/model/base.rb
2244 def with_pk(pk)
2245   if pk && (loader = _with_pk_loader)
2246     loader.first(*pk)
2247   else
2248     first(model.qualified_primary_key_hash(pk))
2249   end
2250 end
with_pk!(pk) click to toggle source

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

     # File lib/sequel/model/base.rb
2254 def with_pk!(pk)
2255   with_pk(pk) || raise(NoMatchingRow.new(self))
2256 end

Private Instance Methods

_force_primary_key_order() click to toggle source

Return the dataset ordered by the model’s primary key. This should not be used if the model does not have a primary key.

     # File lib/sequel/model/base.rb
2262 def _force_primary_key_order
2263   cached_dataset(:_pk_order_ds){order(*model.primary_key)}
2264 end
_primary_key_order() click to toggle source

If the dataset is not already ordered, and the model has a primary key, return a clone ordered by the primary key.

     # File lib/sequel/model/base.rb
2268 def _primary_key_order
2269   if @opts[:order].nil? && model && model.primary_key
2270     _force_primary_key_order
2271   end
2272 end
_with_pk_loader() click to toggle source

A cached placeholder literalizer, if one exists for the current dataset.

     # File lib/sequel/model/base.rb
2275 def _with_pk_loader
2276   cached_placeholder_literalizer(:_with_pk_loader) do |pl|
2277     table = model.table_name
2278     cond = case primary_key = model.primary_key
2279     when Array
2280       primary_key.map{|key| [SQL::QualifiedIdentifier.new(table, key), pl.arg]}
2281     when Symbol
2282       {SQL::QualifiedIdentifier.new(table, primary_key)=>pl.arg}
2283     else
2284       raise(Error, "#{model} does not have a primary key")
2285     end
2286 
2287     where(cond).limit(1)
2288   end
2289 end
non_sql_option?(key) click to toggle source
Calls superclass method
     # File lib/sequel/model/base.rb
2291 def non_sql_option?(key)
2292   super || key == :model
2293 end