module Sequel::Model::DatasetMethods
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 2095 def [](*args) 2096 if args.length == 1 && (i = args[0]) && i.is_a?(Integer) 2097 with_pk(i) 2098 else 2099 super 2100 end 2101 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 2154 def as_hash(key_column=nil, value_column=nil, opts=OPTS) 2155 if key_column 2156 super 2157 else 2158 raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key) 2159 super(pk, value_column, opts) 2160 end 2161 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 2112 def destroy 2113 pr = proc{all(&:destroy).length} 2114 model.use_transactions ? @db.transaction(:server=>opts[:server], &pr) : pr.call 2115 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 2122 def last(*a, &block) 2123 if ds = _primary_key_order 2124 ds.last(*a, &block) 2125 else 2126 super 2127 end 2128 end
The model class associated with this dataset
Artist.dataset.model # => Artist
# File lib/sequel/model/base.rb 2087 def model 2088 @opts[:model] 2089 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 2138 def paged_each(*a, &block) 2139 if ds = _primary_key_order 2140 ds.paged_each(*a, &block) 2141 else 2142 super 2143 end 2144 end
Alias of as_hash
for backwards compatibility.
# File lib/sequel/model/base.rb 2164 def to_hash(*a) 2165 as_hash(*a) 2166 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 2178 def with_pk(pk) 2179 if pk && (loader = _with_pk_loader) 2180 loader.first(*pk) 2181 else 2182 first(model.qualified_primary_key_hash(pk)) 2183 end 2184 end
Same as with_pk
, but raises NoMatchingRow
instead of returning nil if no row matches.
# File lib/sequel/model/base.rb 2188 def with_pk!(pk) 2189 with_pk(pk) || raise(NoMatchingRow.new(self)) 2190 end
Private Instance Methods
If the dataset is not already ordered, and the model has a primary key, return a clone ordered by the primary key.
# File lib/sequel/model/base.rb 2196 def _primary_key_order 2197 if @opts[:order].nil? && model && (pk = model.primary_key) 2198 cached_dataset(:_pk_order_ds){order(*pk)} 2199 end 2200 end
A cached placeholder literalizer, if one exists for the current dataset.
# File lib/sequel/model/base.rb 2203 def _with_pk_loader 2204 cached_placeholder_literalizer(:_with_pk_loader) do |pl| 2205 table = model.table_name 2206 cond = case primary_key = model.primary_key 2207 when Array 2208 primary_key.map{|key| [SQL::QualifiedIdentifier.new(table, key), pl.arg]} 2209 when Symbol 2210 {SQL::QualifiedIdentifier.new(table, primary_key)=>pl.arg} 2211 else 2212 raise(Error, "#{model} does not have a primary key") 2213 end 2214 2215 where(cond).limit(1) 2216 end 2217 end
# File lib/sequel/model/base.rb 2219 def non_sql_option?(key) 2220 super || key == :model 2221 end