DatasetMethods contains methods that all model datasets have.
Public Instance methods
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 2135 def [](*args) 2136 if args.length == 1 && (i = args[0]) && i.is_a?(Integer) 2137 with_pk(i) 2138 else 2139 super 2140 end 2141 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 2195 def as_hash(key_column=nil, value_column=nil, opts=OPTS) 2196 if key_column 2197 super 2198 else 2199 raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key) 2200 super(pk, value_column, opts) 2201 end 2202 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 2152 def destroy 2153 @db.transaction(:server=>opts[:server], :skip_transaction=>model.use_transactions == false) do 2154 all(&:destroy).length 2155 end 2156 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 2163 def last(*a, &block) 2164 if ds = _primary_key_order 2165 ds.last(*a, &block) 2166 else 2167 super 2168 end 2169 end
The model class associated with this dataset
Artist.dataset.model # => Artist
# File lib/sequel/model/base.rb 2127 def model 2128 @opts[:model] 2129 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 2179 def paged_each(*a, &block) 2180 if ds = _primary_key_order 2181 ds.paged_each(*a, &block) 2182 else 2183 super 2184 end 2185 end
Alias of as_hash for backwards compatibility.
# File lib/sequel/model/base.rb 2205 def to_hash(*a) 2206 as_hash(*a) 2207 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 2219 def with_pk(pk) 2220 if pk && (loader = _with_pk_loader) 2221 loader.first(*pk) 2222 else 2223 first(model.qualified_primary_key_hash(pk)) 2224 end 2225 end
Same as with_pk, but raises NoMatchingRow instead of returning nil if no row matches.
# File lib/sequel/model/base.rb 2229 def with_pk!(pk) 2230 with_pk(pk) || raise(NoMatchingRow.new(self)) 2231 end