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 2156 def [](*args) 2157 if args.length == 1 && (i = args[0]) && i.is_a?(Integer) 2158 with_pk(i) 2159 else 2160 super 2161 end 2162 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 2216 def as_hash(key_column=nil, value_column=nil, opts=OPTS) 2217 if key_column 2218 super 2219 else 2220 raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key) 2221 super(pk, value_column, opts) 2222 end 2223 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 2173 def destroy 2174 @db.transaction(:server=>opts[:server], :skip_transaction=>model.use_transactions == false) do 2175 all(&:destroy).length 2176 end 2177 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 2184 def last(*a, &block) 2185 if ds = _primary_key_order 2186 ds.last(*a, &block) 2187 else 2188 super 2189 end 2190 end
The model class associated with this dataset
Artist.dataset.model # => Artist
# File lib/sequel/model/base.rb 2148 def model 2149 @opts[:model] 2150 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 2200 def paged_each(*a, &block) 2201 if ds = _primary_key_order 2202 ds.paged_each(*a, &block) 2203 else 2204 super 2205 end 2206 end
Alias of as_hash for backwards compatibility.
# File lib/sequel/model/base.rb 2226 def to_hash(*a) 2227 as_hash(*a) 2228 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 2240 def with_pk(pk) 2241 if pk && (loader = _with_pk_loader) 2242 loader.first(*pk) 2243 else 2244 first(model.qualified_primary_key_hash(pk)) 2245 end 2246 end
Same as with_pk, but raises NoMatchingRow instead of returning nil if no row matches.
# File lib/sequel/model/base.rb 2250 def with_pk!(pk) 2251 with_pk(pk) || raise(NoMatchingRow.new(self)) 2252 end