Module | Sequel::Model::DatasetMethods |
In: |
lib/sequel/model/base.rb
|
Dataset methods are methods that the model class extends its dataset with in the call to set_dataset.
model | [RW] |
The model class associated with this dataset
Artist.dataset.model # => Artist |
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, line 2380 2380: def [](*args) 2381: if args.length == 1 && (i = args.at(0)) && i.is_a?(Integer) 2382: with_pk(i) 2383: else 2384: super 2385: end 2386: 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, line 2397 2397: def destroy 2398: pr = proc{all(&:destroy).length} 2399: model.use_transactions ? @db.transaction(:server=>opts[:server], &pr) : pr.call 2400: end
Allow Sequel::Model classes to be used as dataset arguments when graphing:
Artist.graph(Album, :artist_id=>id) # SELECT artists.id, artists.name, albums.id AS albums_id, albums.artist_id, albums.name AS albums_name # FROM artists LEFT OUTER JOIN albums ON (albums.artist_id = artists.id)
# File lib/sequel/model/base.rb, line 2407 2407: def graph(table, *args, &block) 2408: if table.is_a?(Class) && table < Sequel::Model 2409: super(table.dataset, *args, &block) 2410: else 2411: super 2412: end 2413: end
Handle Sequel::Model instances when inserting, using the model instance‘s values for the insert, unless the model instance can be used directly in SQL.
Album.insert(Album.load(:name=>'A')) # INSERT INTO albums (name) VALUES ('A')
# File lib/sequel/model/base.rb, line 2421 2421: def insert_sql(*values) 2422: if values.size == 1 && (v = values.at(0)).is_a?(Sequel::Model) && !v.respond_to?(:sql_literal_append) 2423: super(v.to_hash) 2424: else 2425: super 2426: end 2427: end
Allow Sequel::Model classes to be used as table name arguments in dataset join methods:
Artist.join(Album, :artist_id=>id) # SELECT * FROM artists INNER JOIN albums ON (albums.artist_id = artists.id)
# File lib/sequel/model/base.rb, line 2434 2434: def join_table(type, table, *args, &block) 2435: if table.is_a?(Class) && table < Sequel::Model 2436: if table.dataset.simple_select_all? 2437: super(type, table.table_name, *args, &block) 2438: else 2439: super(type, table.dataset, *args, &block) 2440: end 2441: else 2442: super 2443: end 2444: 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, line 2451 2451: def last(*a, &block) 2452: if opts[:order].nil? && model && (pk = model.primary_key) 2453: order(*pk).last(*a, &block) 2454: else 2455: super 2456: end 2457: 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, line 2467 2467: def paged_each(*a, &block) 2468: if opts[:order].nil? && model && (pk = model.primary_key) 2469: order(*pk).paged_each(*a, &block) 2470: else 2471: super 2472: end 2473: end
This allows you to call to_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.to_hash # SELECT * FROM artists # => {1=>#<Artist {:id=>1, ...}>, # 2=>#<Artist {:id=>2, ...}>, # ...}
# File lib/sequel/model/base.rb, line 2483 2483: def to_hash(key_column=nil, value_column=nil, opts=OPTS) 2484: if key_column 2485: super 2486: else 2487: raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key) 2488: super(pk, value_column, opts) 2489: end 2490: 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, line 2502 2502: def with_pk(pk) 2503: first(model.qualified_primary_key_hash(pk)) 2504: end
Same as with_pk, but raises NoMatchingRow instead of returning nil if no row matches.
# File lib/sequel/model/base.rb, line 2508 2508: def with_pk!(pk) 2509: with_pk(pk) || raise(NoMatchingRow.new(self)) 2510: end