module Sequel::Model::DatasetMethods
DatasetMethods
contains methods that all model datasets have.
Public Instance Methods
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
# 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
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, ...}>, # ...}
# 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 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 2142 def destroy 2143 pr = proc{all(&:destroy).length} 2144 model.use_transactions ? @db.transaction(:server=>opts[:server], &pr) : pr.call 2145 end
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
# 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
The model class associated with this dataset
Artist.dataset.model # => Artist
# File lib/sequel/model/base.rb 2117 def model 2118 @opts[:model] 2119 end
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 # ...
# 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
Alias of as_hash
for backwards compatibility.
# File lib/sequel/model/base.rb 2194 def to_hash(*a) 2195 as_hash(*a) 2196 end
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 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
Same as with_pk
, but raises NoMatchingRow
instead of returning nil if no row matches.
# File lib/sequel/model/base.rb 2218 def with_pk!(pk) 2219 with_pk(pk) || raise(NoMatchingRow.new(self)) 2220 end
Private Instance Methods
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 2226 def _primary_key_order 2227 if @opts[:order].nil? && model && (pk = model.primary_key) 2228 cached_dataset(:_pk_order_ds){order(*pk)} 2229 end 2230 end
A cached placeholder literalizer, if one exists for the current dataset.
# File lib/sequel/model/base.rb 2233 def _with_pk_loader 2234 cached_placeholder_literalizer(:_with_pk_loader) do |pl| 2235 table = model.table_name 2236 cond = case primary_key = model.primary_key 2237 when Array 2238 primary_key.map{|key| [SQL::QualifiedIdentifier.new(table, key), pl.arg]} 2239 when Symbol 2240 {SQL::QualifiedIdentifier.new(table, primary_key)=>pl.arg} 2241 else 2242 raise(Error, "#{model} does not have a primary key") 2243 end 2244 2245 where(cond).limit(1) 2246 end 2247 end
# File lib/sequel/model/base.rb 2249 def non_sql_option?(key) 2250 super || key == :model 2251 end