Module | Sequel::Model::DatasetMethods |
In: |
lib/sequel/model/base.rb
|
DatasetMethods contains methods that all model datasets have.
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 2026 2026: def [](*args) 2027: if args.length == 1 && (i = args[0]) && i.is_a?(Integer) 2028: with_pk(i) 2029: else 2030: super 2031: end 2032: 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, line 2085 2085: def as_hash(key_column=nil, value_column=nil, opts=OPTS) 2086: if key_column 2087: super 2088: else 2089: raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key) 2090: super(pk, value_column, opts) 2091: end 2092: 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 2043 2043: def destroy 2044: pr = proc{all(&:destroy).length} 2045: model.use_transactions ? @db.transaction(:server=>opts[:server], &pr) : pr.call 2046: 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 2053 2053: def last(*a, &block) 2054: if ds = _primary_key_order 2055: ds.last(*a, &block) 2056: else 2057: super 2058: end 2059: 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 2069 2069: def paged_each(*a, &block) 2070: if ds = _primary_key_order 2071: ds.paged_each(*a, &block) 2072: else 2073: super 2074: end 2075: 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 2109 2109: def with_pk(pk) 2110: if pk && (loader = _with_pk_loader) 2111: loader.first(*pk) 2112: else 2113: first(model.qualified_primary_key_hash(pk)) 2114: end 2115: end
Same as with_pk, but raises NoMatchingRow instead of returning nil if no row matches.
# File lib/sequel/model/base.rb, line 2119 2119: def with_pk!(pk) 2120: with_pk(pk) || raise(NoMatchingRow.new(self)) 2121: end