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 2138 def [](*args) 2139 if args.length == 1 && (i = args[0]) && i.is_a?(Integer) 2140 with_pk(i) 2141 else 2142 super 2143 end 2144 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 2198 def as_hash(key_column=nil, value_column=nil, opts=OPTS) 2199 if key_column 2200 super 2201 else 2202 raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key) 2203 super(pk, value_column, opts) 2204 end 2205 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 2155 def destroy 2156 @db.transaction(:server=>opts[:server], :skip_transaction=>model.use_transactions == false) do 2157 all(&:destroy).length 2158 end 2159 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 2166 def last(*a, &block) 2167 if ds = _primary_key_order 2168 ds.last(*a, &block) 2169 else 2170 super 2171 end 2172 end
The model class associated with this dataset
Artist.dataset.model # => Artist
# File lib/sequel/model/base.rb 2130 def model 2131 @opts[:model] 2132 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 2182 def paged_each(*a, &block) 2183 if ds = _primary_key_order 2184 ds.paged_each(*a, &block) 2185 else 2186 super 2187 end 2188 end
Alias of as_hash for backwards compatibility.
# File lib/sequel/model/base.rb 2208 def to_hash(*a) 2209 as_hash(*a) 2210 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 2222 def with_pk(pk) 2223 if pk && (loader = _with_pk_loader) 2224 loader.first(*pk) 2225 else 2226 first(model.qualified_primary_key_hash(pk)) 2227 end 2228 end
Same as with_pk, but raises NoMatchingRow instead of returning nil if no row matches.
# File lib/sequel/model/base.rb 2232 def with_pk!(pk) 2233 with_pk(pk) || raise(NoMatchingRow.new(self)) 2234 end