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 2178 def [](*args) 2179 if args.length == 1 && (i = args[0]) && i.is_a?(Integer) 2180 with_pk(i) 2181 else 2182 super 2183 end 2184 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 2238 def as_hash(key_column=nil, value_column=nil, opts=OPTS) 2239 if key_column 2240 super 2241 else 2242 raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key) 2243 super(pk, value_column, opts) 2244 end 2245 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 2195 def destroy 2196 @db.transaction(:server=>opts[:server], :skip_transaction=>model.use_transactions == false) do 2197 all(&:destroy).length 2198 end 2199 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 2206 def last(*a, &block) 2207 if ds = _primary_key_order 2208 ds.last(*a, &block) 2209 else 2210 super 2211 end 2212 end
The model class associated with this dataset
Artist.dataset.model # => Artist
# File lib/sequel/model/base.rb 2170 def model 2171 @opts[:model] 2172 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 2222 def paged_each(*a, &block) 2223 if ds = _primary_key_order 2224 ds.paged_each(*a, &block) 2225 else 2226 super 2227 end 2228 end
Alias of as_hash for backwards compatibility.
# File lib/sequel/model/base.rb 2248 def to_hash(*a) 2249 as_hash(*a) 2250 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 2262 def with_pk(pk) 2263 if pk && (loader = _with_pk_loader) 2264 loader.first(*pk) 2265 else 2266 first(model.qualified_primary_key_hash(pk)) 2267 end 2268 end
Same as with_pk, but raises NoMatchingRow instead of returning nil if no row matches.
# File lib/sequel/model/base.rb 2272 def with_pk!(pk) 2273 with_pk(pk) || raise(NoMatchingRow.new(self)) 2274 end