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 2143 def [](*args) 2144 if args.length == 1 && (i = args[0]) && i.is_a?(Integer) 2145 with_pk(i) 2146 else 2147 super 2148 end 2149 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 2203 def as_hash(key_column=nil, value_column=nil, opts=OPTS) 2204 if key_column 2205 super 2206 else 2207 raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key) 2208 super(pk, value_column, opts) 2209 end 2210 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 2160 def destroy 2161 @db.transaction(:server=>opts[:server], :skip_transaction=>model.use_transactions == false) do 2162 all(&:destroy).length 2163 end 2164 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 2171 def last(*a, &block) 2172 if ds = _primary_key_order 2173 ds.last(*a, &block) 2174 else 2175 super 2176 end 2177 end
The model class associated with this dataset
Artist.dataset.model # => Artist
# File lib/sequel/model/base.rb 2135 def model 2136 @opts[:model] 2137 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 2187 def paged_each(*a, &block) 2188 if ds = _primary_key_order 2189 ds.paged_each(*a, &block) 2190 else 2191 super 2192 end 2193 end
Alias of as_hash for backwards compatibility.
# File lib/sequel/model/base.rb 2213 def to_hash(*a) 2214 as_hash(*a) 2215 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 2227 def with_pk(pk) 2228 if pk && (loader = _with_pk_loader) 2229 loader.first(*pk) 2230 else 2231 first(model.qualified_primary_key_hash(pk)) 2232 end 2233 end
Same as with_pk, but raises NoMatchingRow instead of returning nil if no row matches.
# File lib/sequel/model/base.rb 2237 def with_pk!(pk) 2238 with_pk(pk) || raise(NoMatchingRow.new(self)) 2239 end