Module: Sequel::Model::DatasetMethods

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

[Source]

      # File lib/sequel/model/base.rb, line 2027
2027:       def [](*args)
2028:         if args.length == 1 && (i = args.at(0)) && i.is_a?(Integer)
2029:           with_pk(i)
2030:         else
2031:           super
2032:         end
2033:       end

destroy()

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)
  # ...

[Source]

      # File lib/sequel/model/base.rb, line 2044
2044:       def destroy
2045:         pr = proc{all{|r| r.destroy}.length}
2046:         model.use_transactions ? @db.transaction(:server=>opts[:server], &pr) : pr.call
2047:       end

graph(table, *args, &block)

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)

[Source]

      # File lib/sequel/model/base.rb, line 2054
2054:       def graph(table, *args, &block)
2055:         if table.is_a?(Class) && table < Sequel::Model
2056:           super(table.dataset, *args, &block)
2057:         else
2058:           super
2059:         end
2060:       end

insert_sql(*values)

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')

[Source]

      # File lib/sequel/model/base.rb, line 2068
2068:       def insert_sql(*values)
2069:         if values.size == 1 && (v = values.at(0)).is_a?(Sequel::Model) && !v.respond_to?(:sql_literal_append)
2070:           super(v.to_hash)
2071:         else
2072:           super
2073:         end
2074:       end

join_table(type, table, *args, &block)

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)

[Source]

      # File lib/sequel/model/base.rb, line 2081
2081:       def join_table(type, table, *args, &block)
2082:         if table.is_a?(Class) && table < Sequel::Model
2083:           if table.dataset.simple_select_all?
2084:             super(type, table.table_name, *args, &block)
2085:           else
2086:             super(type, table.dataset, *args, &block)
2087:           end
2088:         else
2089:           super
2090:         end
2091:       end

last(*a, &block)

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

[Source]

      # File lib/sequel/model/base.rb, line 2098
2098:       def last(*a, &block)
2099:         if opts[:order].nil? && model && (pk = model.primary_key)
2100:           order(*pk).last(*a, &block)
2101:         else
2102:           super
2103:         end
2104:       end

paged_each(*a, &block)

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
  # ...

[Source]

      # File lib/sequel/model/base.rb, line 2114
2114:       def paged_each(*a, &block)
2115:         if opts[:order].nil? && model && (pk = model.primary_key)
2116:           order(*pk).paged_each(*a, &block)
2117:         else
2118:           super
2119:         end
2120:       end

to_hash(key_column=nil, value_column=nil)

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, ...}>,
  #     ...}

[Source]

      # File lib/sequel/model/base.rb, line 2130
2130:       def to_hash(key_column=nil, value_column=nil)
2131:         if key_column
2132:           super
2133:         else
2134:           raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key)
2135:           super(pk, value_column) 
2136:         end
2137:       end

with_pk(pk)

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 (id = 1) LIMIT 1

  # Composite primary key
  Artist.dataset.with_pk([1, 2]) # SELECT * FROM artists
                                 # WHERE ((id1 = 1) AND (id2 = 2)) LIMIT 1

[Source]

      # File lib/sequel/model/base.rb, line 2148
2148:       def with_pk(pk)
2149:         first(model.qualified_primary_key_hash(pk))
2150:       end

with_pk!(pk)

Same as with_pk, but raises NoMatchingRow instead of returning nil if no row matches.

[Source]

      # File lib/sequel/model/base.rb, line 2154
2154:       def with_pk!(pk)
2155:         with_pk(pk) || raise(NoMatchingRow)
2156:       end

Methods

Attributes

Public Instance methods