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 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
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 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 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
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 2188 def last(*a, &block) 2189 if ds = _primary_key_order 2190 ds.last(*a, &block) 2191 else 2192 super 2193 end 2194 end
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
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 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
Alias of as_hash for backwards compatibility.
# File lib/sequel/model/base.rb 2230 def to_hash(*a) 2231 as_hash(*a) 2232 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 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
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