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 2101 def [](*args) 2102 if args.length == 1 && (i = args[0]) && i.is_a?(Integer) 2103 with_pk(i) 2104 else 2105 super 2106 end 2107 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 2160 def as_hash(key_column=nil, value_column=nil, opts=OPTS) 2161 if key_column 2162 super 2163 else 2164 raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key) 2165 super(pk, value_column, opts) 2166 end 2167 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 2118 def destroy 2119 pr = proc{all(&:destroy).length} 2120 model.use_transactions ? @db.transaction(:server=>opts[:server], &pr) : pr.call 2121 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 2128 def last(*a, &block) 2129 if ds = _primary_key_order 2130 ds.last(*a, &block) 2131 else 2132 super 2133 end 2134 end
The model class associated with this dataset
Artist.dataset.model # => Artist
# File lib/sequel/model/base.rb 2093 def model 2094 @opts[:model] 2095 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 2144 def paged_each(*a, &block) 2145 if ds = _primary_key_order 2146 ds.paged_each(*a, &block) 2147 else 2148 super 2149 end 2150 end
Alias of as_hash
for backwards compatibility.
# File lib/sequel/model/base.rb 2170 def to_hash(*a) 2171 as_hash(*a) 2172 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 2184 def with_pk(pk) 2185 if pk && (loader = _with_pk_loader) 2186 loader.first(*pk) 2187 else 2188 first(model.qualified_primary_key_hash(pk)) 2189 end 2190 end
Same as with_pk
, but raises NoMatchingRow
instead of returning nil if no row matches.
# File lib/sequel/model/base.rb 2194 def with_pk!(pk) 2195 with_pk(pk) || raise(NoMatchingRow.new(self)) 2196 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 2202 def _primary_key_order 2203 if @opts[:order].nil? && model && (pk = model.primary_key) 2204 cached_dataset(:_pk_order_ds){order(*pk)} 2205 end 2206 end
A cached placeholder literalizer, if one exists for the current dataset.
# File lib/sequel/model/base.rb 2209 def _with_pk_loader 2210 cached_placeholder_literalizer(:_with_pk_loader) do |pl| 2211 table = model.table_name 2212 cond = case primary_key = model.primary_key 2213 when Array 2214 primary_key.map{|key| [SQL::QualifiedIdentifier.new(table, key), pl.arg]} 2215 when Symbol 2216 {SQL::QualifiedIdentifier.new(table, primary_key)=>pl.arg} 2217 else 2218 raise(Error, "#{model} does not have a primary key") 2219 end 2220 2221 where(cond).limit(1) 2222 end 2223 end
# File lib/sequel/model/base.rb 2225 def non_sql_option?(key) 2226 super || key == :model 2227 end