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 2037 2037: def [](*args) 2038: if args.length == 1 && (i = args[0]) && i.is_a?(Integer) 2039: with_pk(i) 2040: else 2041: super 2042: end 2043: 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 2096 2096: def as_hash(key_column=nil, value_column=nil, opts=OPTS) 2097: if key_column 2098: super 2099: else 2100: raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key) 2101: super(pk, value_column, opts) 2102: end 2103: 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 2054 2054: def destroy 2055: pr = proc{all(&:destroy).length} 2056: model.use_transactions ? @db.transaction(:server=>opts[:server], &pr) : pr.call 2057: 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 2064 2064: def last(*a, &block) 2065: if ds = _primary_key_order 2066: ds.last(*a, &block) 2067: else 2068: super 2069: end 2070: 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 2080 2080: def paged_each(*a, &block) 2081: if ds = _primary_key_order 2082: ds.paged_each(*a, &block) 2083: else 2084: super 2085: end 2086: 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 2120 2120: def with_pk(pk) 2121: if pk && (loader = _with_pk_loader) 2122: loader.first(*pk) 2123: else 2124: first(model.qualified_primary_key_hash(pk)) 2125: end 2126: end
Same as with_pk, but raises NoMatchingRow instead of returning nil if no row matches.
# File lib/sequel/model/base.rb, line 2130 2130: def with_pk!(pk) 2131: with_pk(pk) || raise(NoMatchingRow.new(self)) 2132: end