Dataset methods are methods that the model class extends its dataset with in the call to set_dataset.
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 2025 def [](*args) if args.length == 1 && (i = args.at(0)) && i.is_a?(Integer) with_pk(i) else super end 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 2042 def destroy pr = proc{all{|r| r.destroy}.length} model.use_transactions ? @db.transaction(:server=>opts[:server], &pr) : pr.call 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 2052 def graph(table, *args, &block) if table.is_a?(Class) && table < Sequel::Model super(table.dataset, *args, &block) else super end 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 2066 def insert_sql(*values) if values.size == 1 && (v = values.at(0)).is_a?(Sequel::Model) && !v.respond_to?(:sql_literal_append) super(v.to_hash) else super end 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 2079 def join_table(type, table, *args, &block) if table.is_a?(Class) && table < Sequel::Model if table.dataset.simple_select_all? super(type, table.table_name, *args, &block) else super(type, table.dataset, *args, &block) end else super end 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 2096 def last(*a, &block) if opts[:order].nil? && model && (pk = model.primary_key) order(*pk).last(*a, &block) else super end 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 2112 def paged_each(*a, &block) if opts[:order].nil? && model && (pk = model.primary_key) order(*pk).paged_each(*a, &block) else super end 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 2128 def to_hash(key_column=nil, value_column=nil) if key_column super else raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key) super(pk, value_column) end 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 (id = 1) LIMIT 1 # Composite primary key Artist.dataset.with_pk([1, 2]) # SELECT * FROM artists # WHERE ((id1 = 1) AND (id2 = 2)) LIMIT 1
# File lib/sequel/model/base.rb, line 2146 def with_pk(pk) first(model.qualified_primary_key_hash(pk)) end
Same as with_pk, but raises NoMatchingRow instead of returning nil if no row matches.
# File lib/sequel/model/base.rb, line 2152 def with_pk!(pk) with_pk(pk) || raise(NoMatchingRow) end
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