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 1732 1732: def [](*args) 1733: if args.length == 1 && (i = args.at(0)) && i.is_a?(Integer) 1734: with_pk(i) 1735: else 1736: super 1737: end 1738: 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 1749 1749: def destroy 1750: pr = proc{all{|r| r.destroy}.length} 1751: model.use_transactions ? @db.transaction(:server=>opts[:server], &pr) : pr.call 1752: 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 1762 1762: def to_hash(key_column=nil, value_column=nil) 1763: if key_column 1764: super 1765: else 1766: raise(Sequel::Error, "No primary key for model") unless model and pk = model.primary_key 1767: super(pk, value_column) 1768: end 1769: end
Given a primary key value, return the first record in the dataset with that primary key value.
# 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 1780 1780: def with_pk(pk) 1781: first(model.qualified_primary_key_hash(pk)) 1782: end