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 2287 def [](*args) 2288 if args.length == 1 && (i = args[0]) && i.is_a?(Integer) 2289 with_pk(i) 2290 else 2291 super 2292 end 2293 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 2347 def as_hash(key_column=nil, value_column=nil, opts=OPTS) 2348 if key_column 2349 super 2350 else 2351 raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key) 2352 super(pk, value_column, opts) 2353 end 2354 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 2304 def destroy 2305 @db.transaction(:server=>opts[:server], :skip_transaction=>model.use_transactions == false) do 2306 all(&:destroy).length 2307 end 2308 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 2315 def last(*a, &block) 2316 if ds = _primary_key_order 2317 ds.last(*a, &block) 2318 else 2319 super 2320 end 2321 end
The model class associated with this dataset
Artist.dataset.model # => Artist
# File lib/sequel/model/base.rb 2279 def model 2280 @opts[:model] 2281 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 2331 def paged_each(*a, &block) 2332 if ds = _primary_key_order 2333 ds.paged_each(*a, &block) 2334 else 2335 super 2336 end 2337 end
Alias of as_hash for backwards compatibility.
# File lib/sequel/model/base.rb 2357 def to_hash(*a) 2358 as_hash(*a) 2359 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 2371 def with_pk(pk) 2372 if pk && (loader = _with_pk_loader) 2373 loader.first(*pk) 2374 else 2375 first(model.qualified_primary_key_hash(pk)) 2376 end 2377 end
Same as with_pk, but raises NoMatchingRow instead of returning nil if no row matches.
# File lib/sequel/model/base.rb 2381 def with_pk!(pk) 2382 with_pk(pk) || raise(NoMatchingRow.new(self)) 2383 end