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 2088 def [](*args) 2089 if args.length == 1 && (i = args[0]) && i.is_a?(Integer) 2090 with_pk(i) 2091 else 2092 super 2093 end 2094 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 2147 def as_hash(key_column=nil, value_column=nil, opts=OPTS) 2148 if key_column 2149 super 2150 else 2151 raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key) 2152 super(pk, value_column, opts) 2153 end 2154 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 2105 def destroy 2106 pr = proc{all(&:destroy).length} 2107 model.use_transactions ? @db.transaction(:server=>opts[:server], &pr) : pr.call 2108 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 2115 def last(*a, &block) 2116 if ds = _primary_key_order 2117 ds.last(*a, &block) 2118 else 2119 super 2120 end 2121 end
The model class associated with this dataset
Artist.dataset.model # => Artist
# File lib/sequel/model/base.rb 2080 def model 2081 @opts[:model] 2082 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 2131 def paged_each(*a, &block) 2132 if ds = _primary_key_order 2133 ds.paged_each(*a, &block) 2134 else 2135 super 2136 end 2137 end
Alias of as_hash
for backwards compatibility.
# File lib/sequel/model/base.rb 2157 def to_hash(*a) 2158 as_hash(*a) 2159 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 2171 def with_pk(pk) 2172 if pk && (loader = _with_pk_loader) 2173 loader.first(*pk) 2174 else 2175 first(model.qualified_primary_key_hash(pk)) 2176 end 2177 end
Same as with_pk
, but raises NoMatchingRow
instead of returning nil if no row matches.
# File lib/sequel/model/base.rb 2181 def with_pk!(pk) 2182 with_pk(pk) || raise(NoMatchingRow.new(self)) 2183 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 2189 def _primary_key_order 2190 if @opts[:order].nil? && model && (pk = model.primary_key) 2191 cached_dataset(:_pk_order_ds){order(*pk)} 2192 end 2193 end
A cached placeholder literalizer, if one exists for the current dataset.
# File lib/sequel/model/base.rb 2196 def _with_pk_loader 2197 cached_placeholder_literalizer(:_with_pk_loader) do |pl| 2198 table = model.table_name 2199 cond = case primary_key = model.primary_key 2200 when Array 2201 primary_key.map{|key| [SQL::QualifiedIdentifier.new(table, key), pl.arg]} 2202 when Symbol 2203 {SQL::QualifiedIdentifier.new(table, primary_key)=>pl.arg} 2204 else 2205 raise(Error, "#{model} does not have a primary key") 2206 end 2207 2208 where(cond).limit(1) 2209 end 2210 end
# File lib/sequel/model/base.rb 2212 def non_sql_option?(key) 2213 super || key == :model 2214 end