module Sequel::Model::DatasetMethods
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 2279 def [](*args) 2280 if args.length == 1 && (i = args[0]) && i.is_a?(Integer) 2281 with_pk(i) 2282 else 2283 super 2284 end 2285 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 2339 def as_hash(key_column=nil, value_column=nil, opts=OPTS) 2340 if key_column 2341 super 2342 else 2343 raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key) 2344 super(pk, value_column, opts) 2345 end 2346 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 2296 def destroy 2297 @db.transaction(:server=>opts[:server], :skip_transaction=>model.use_transactions == false) do 2298 all(&:destroy).length 2299 end 2300 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 2307 def last(*a, &block) 2308 if ds = _primary_key_order 2309 ds.last(*a, &block) 2310 else 2311 super 2312 end 2313 end
The model class associated with this dataset
Artist.dataset.model # => Artist
# File lib/sequel/model/base.rb 2271 def model 2272 @opts[:model] 2273 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 2323 def paged_each(*a, &block) 2324 if ds = _primary_key_order 2325 ds.paged_each(*a, &block) 2326 else 2327 super 2328 end 2329 end
Alias of as_hash for backwards compatibility.
# File lib/sequel/model/base.rb 2349 def to_hash(*a) 2350 as_hash(*a) 2351 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 2363 def with_pk(pk) 2364 if pk && (loader = _with_pk_loader) 2365 loader.first(*pk) 2366 else 2367 first(model.qualified_primary_key_hash(pk)) 2368 end 2369 end
Same as with_pk, but raises NoMatchingRow instead of returning nil if no row matches.
# File lib/sequel/model/base.rb 2373 def with_pk!(pk) 2374 with_pk(pk) || raise(NoMatchingRow.new(self)) 2375 end
Private Instance Methods
Return the dataset ordered by the model’s primary key. This should not be used if the model does not have a primary key.
# File lib/sequel/model/base.rb 2381 def _force_primary_key_order 2382 cached_dataset(:_pk_order_ds){order(*unambiguous_primary_key)} 2383 end
If the dataset is not already ordered, and the model has a primary key, return a clone ordered by the primary key.
# File lib/sequel/model/base.rb 2387 def _primary_key_order 2388 if @opts[:order].nil? && model && model.primary_key 2389 _force_primary_key_order 2390 end 2391 end
A cached placeholder literalizer, if one exists for the current dataset.
# File lib/sequel/model/base.rb 2394 def _with_pk_loader 2395 cached_placeholder_literalizer(:_with_pk_loader) do |pl| 2396 table = model.table_name 2397 cond = case primary_key = model.primary_key 2398 when Array 2399 primary_key.map{|key| [SQL::QualifiedIdentifier.new(table, key), pl.arg]} 2400 when Symbol 2401 {SQL::QualifiedIdentifier.new(table, primary_key)=>pl.arg} 2402 else 2403 raise(Error, "#{model} does not have a primary key") 2404 end 2405 2406 where(cond).limit(1) 2407 end 2408 end
# File lib/sequel/model/base.rb 2419 def non_sql_option?(key) 2420 super || key == :model 2421 end
The primary key for the dataset’s model, qualified if the dataset is joined.
# File lib/sequel/model/base.rb 2411 def unambiguous_primary_key 2412 if joined_dataset? 2413 model.qualified_primary_key 2414 else 2415 model.primary_key 2416 end 2417 end