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, line 2505 def [](*args) if args.length == 1 && (i = args.at(0)) && i.is_a?(Integer) with_pk(i) else super end 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, line 2522 def destroy pr = proc{all(&:destroy).length} model.use_transactions ? @db.transaction(:server=>opts[:server], &pr) : pr.call end
Allow Sequel::Model classes to be used as dataset arguments when graphing:
Artist.graph(Album, :artist_id=>id) # SELECT artists.id, artists.name, albums.id AS albums_id, albums.artist_id, albums.name AS albums_name # FROM artists LEFT OUTER JOIN albums ON (albums.artist_id = artists.id)
# File lib/sequel/model/base.rb, line 2532 def graph(table, *args, &block) if table.is_a?(Class) && table < Sequel::Model super(table.dataset, *args, &block) else super end end
Handle Sequel::Model instances when inserting, using the model instance's values for the insert, unless the model instance can be used directly in SQL.
Album.insert(Album.load(:name=>'A')) # INSERT INTO albums (name) VALUES ('A')
# File lib/sequel/model/base.rb, line 2546 def insert_sql(*values) if values.size == 1 && (v = values.at(0)).is_a?(Sequel::Model) && !v.respond_to?(:sql_literal_append) super(v.to_hash) else super end end
Allow Sequel::Model classes to be used as table name arguments in dataset join methods:
Artist.join(Album, :artist_id=>id) # SELECT * FROM artists INNER JOIN albums ON (albums.artist_id = artists.id)
# File lib/sequel/model/base.rb, line 2559 def join_table(type, table, *args, &block) if table.is_a?(Class) && table < Sequel::Model if table.dataset.simple_select_all? super(type, table.table_name, *args, &block) else super(type, table.dataset, *args, &block) end else super end 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, line 2576 def last(*a, &block) if ds = _primary_key_order ds.last(*a, &block) else super end end
The model class associated with this dataset
Artist.dataset.model # => Artist
# File lib/sequel/model/base.rb, line 2497 def model @opts[:model] 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, line 2592 def paged_each(*a, &block) if ds = _primary_key_order ds.paged_each(*a, &block) else super end end
This allows you to call to_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.to_hash # SELECT * FROM artists # => {1=>#<Artist {:id=>1, ...}>, # 2=>#<Artist {:id=>2, ...}>, # ...}
# File lib/sequel/model/base.rb, line 2608 def to_hash(key_column=nil, value_column=nil, opts=OPTS) if key_column super else raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key) super(pk, value_column, opts) end end
Return an array of all rows matching the given filter condition, also yielding each row to the given block. Basically the same as where(cond).all(&block), except it can be optimized to not create an intermediate dataset.
Artist.where_all(:id=>[1,2,3]) # SELECT * FROM artists WHERE (id IN (1, 2, 3))
# File lib/sequel/model/base.rb, line 2623 def where_all(cond, &block) if loader = _model_where_loader loader.all(filter_expr(cond), &block) else where(cond).all(&block) end end
Iterate over all rows matching the given filter condition, yielding each row to the given block. Basically the same as where(cond).each(&block), except it can be optimized to not create an intermediate dataset.
Artist.where_each(:id=>[1,2,3]){|row| p row} # SELECT * FROM artists WHERE (id IN (1, 2, 3))
# File lib/sequel/model/base.rb, line 2637 def where_each(cond, &block) if loader = _model_where_loader loader.each(filter_expr(cond), &block) else where(cond).each(&block) end end
Filter the datasets using the given filter condition, then return a single value. This assumes that the dataset has already been setup to limit the selection to a single column. Basically the same as where(cond).single_value, except it can be optimized to not create an intermediate dataset.
Artist.select(:name).where_single_value(:id=>1) # SELECT name FROM artists WHERE (id = 1) LIMIT 1
# File lib/sequel/model/base.rb, line 2652 def where_single_value(cond) if loader = cached_placeholder_literalizer(:_model_where_single_value_loader) do |pl| single_value_ds.where(pl.arg) end loader.get(filter_expr(cond)) else where(cond).single_value end 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, line 2673 def with_pk(pk) if pk && (loader = _with_pk_loader) loader.first(*pk) else first(model.qualified_primary_key_hash(pk)) end end
Same as #with_pk, but raises NoMatchingRow instead of returning nil if no row matches.
# File lib/sequel/model/base.rb, line 2683 def with_pk!(pk) with_pk(pk) || raise(NoMatchingRow.new(self)) end
Private Instance Methods
Loader used for #where_all and where_each.
# File lib/sequel/model/base.rb, line 2690 def _model_where_loader cached_placeholder_literalizer(:_model_where_loader) do |pl| where(pl.arg) end end
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, line 2698 def _primary_key_order if @opts[:order].nil? && model && (pk = model.primary_key) cached_dataset(:_pk_order_ds){order(*pk)} end end
A cached placeholder literalizer, if one exists for the current dataset.
# File lib/sequel/model/base.rb, line 2705 def _with_pk_loader cached_placeholder_literalizer(:_with_pk_loader) do |pl| table = model.table_name cond = case primary_key = model.primary_key when Array primary_key.map{|key| [SQL::QualifiedIdentifier.new(table, key), pl.arg]} when Symbol {SQL::QualifiedIdentifier.new(table, primary_key)=>pl.arg} else raise(Error, "#{model} does not have a primary key") end where(cond).limit(1) end end