module Sequel::Model::DatasetMethods
DatasetMethods
contains methods that all model datasets have.
Public Instance Methods
Source
# File lib/sequel/model/base.rb 2160 def [](*args) 2161 if args.length == 1 && (i = args[0]) && i.is_a?(Integer) 2162 with_pk(i) 2163 else 2164 super 2165 end 2166 end
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
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# File lib/sequel/model/base.rb 2220 def as_hash(key_column=nil, value_column=nil, opts=OPTS) 2221 if key_column 2222 super 2223 else 2224 raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key) 2225 super(pk, value_column, opts) 2226 end 2227 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, ...}>, # ...}
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# File lib/sequel/model/base.rb 2177 def destroy 2178 @db.transaction(:server=>opts[:server], :skip_transaction=>model.use_transactions == false) do 2179 all(&:destroy).length 2180 end 2181 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) # ...
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# File lib/sequel/model/base.rb 2188 def last(*a, &block) 2189 if ds = _primary_key_order 2190 ds.last(*a, &block) 2191 else 2192 super 2193 end 2194 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
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# File lib/sequel/model/base.rb 2152 def model 2153 @opts[:model] 2154 end
The model class associated with this dataset
Artist.dataset.model # => Artist
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# File lib/sequel/model/base.rb 2204 def paged_each(*a, &block) 2205 if ds = _primary_key_order 2206 ds.paged_each(*a, &block) 2207 else 2208 super 2209 end 2210 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 # ...
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# File lib/sequel/model/base.rb 2230 def to_hash(*a) 2231 as_hash(*a) 2232 end
Alias of as_hash
for backwards compatibility.
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# File lib/sequel/model/base.rb 2244 def with_pk(pk) 2245 if pk && (loader = _with_pk_loader) 2246 loader.first(*pk) 2247 else 2248 first(model.qualified_primary_key_hash(pk)) 2249 end 2250 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
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# File lib/sequel/model/base.rb 2254 def with_pk!(pk) 2255 with_pk(pk) || raise(NoMatchingRow.new(self)) 2256 end
Same as with_pk
, but raises NoMatchingRow
instead of returning nil if no row matches.
Private Instance Methods
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# File lib/sequel/model/base.rb 2262 def _force_primary_key_order 2263 cached_dataset(:_pk_order_ds){order(*model.primary_key)} 2264 end
Return the dataset ordered by the model’s primary key. This should not be used if the model does not have a primary key.
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# File lib/sequel/model/base.rb 2268 def _primary_key_order 2269 if @opts[:order].nil? && model && model.primary_key 2270 _force_primary_key_order 2271 end 2272 end
If the dataset is not already ordered, and the model has a primary key, return a clone ordered by the primary key.
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# File lib/sequel/model/base.rb 2275 def _with_pk_loader 2276 cached_placeholder_literalizer(:_with_pk_loader) do |pl| 2277 table = model.table_name 2278 cond = case primary_key = model.primary_key 2279 when Array 2280 primary_key.map{|key| [SQL::QualifiedIdentifier.new(table, key), pl.arg]} 2281 when Symbol 2282 {SQL::QualifiedIdentifier.new(table, primary_key)=>pl.arg} 2283 else 2284 raise(Error, "#{model} does not have a primary key") 2285 end 2286 2287 where(cond).limit(1) 2288 end 2289 end
A cached placeholder literalizer, if one exists for the current dataset.
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# File lib/sequel/model/base.rb 2291 def non_sql_option?(key) 2292 super || key == :model 2293 end