Module: PostgreSQLCursor::ActiveRecord::Relation::CursorIterators

Defined in:
lib/postgresql_cursor/active_record/relation/cursor_iterators.rb

Instance Method Summary collapse

Instance Method Details

#each_instance(options = {}, &block) ⇒ Object

Public: Like each_row, but returns an instantiated model object to the block

Paramaters: same as each_row

Example:

Post.where(user_id:123).each_instance { |post| post.process }
Post.where(user_id:123).each_instance.map { |post| post.process }

Returns the number of rows yielded to the block


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# File 'lib/postgresql_cursor/active_record/relation/cursor_iterators.rb', line 41

def each_instance(options={}, &block)
  options = {:connection => self.connection}.merge(options)
  cursor = PostgreSQLCursor::Cursor.new(to_unprepared_sql, options)
  return cursor.each_instance(self, &block) if block_given?
  cursor.iterate_type(self)
end

#each_instance_batch(options = {}, &block) ⇒ Object

Public: Like each_row, but yields an array of instantiated model objects to the block

Parameters: same as each_row

Example:

Post.where(user_id:123).each_instance_batch do |batch|
  Post.process_batch(batch)
end
Post.where(user_id:123).each_instance_batch.map do |batch|
  Post.transform_batch(batch)
end

Returns the number of rows yielded to the block


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# File 'lib/postgresql_cursor/active_record/relation/cursor_iterators.rb', line 82

def each_instance_batch(options={}, &block)
  options = {:connection => self.connection}.merge(options)
  cursor = PostgreSQLCursor::Cursor.new(to_unprepared_sql, options)
  return cursor.each_instance_batch(self, &block) if block_given?
  cursor.iterate_type(self).iterate_batched
end

#each_row(options = {}, &block) ⇒ Object Also known as: each_hash

Public: Executes the query, returning each row as a hash to the given block.

options - Hash to control

fraction: 0.1..1.0    - The cursor_tuple_fraction (default 1.0)
block_size: 1..n      - The number of rows to fetch per db block fetch
while: value          - Exits loop when block does not return this value.
until: value          - Exits loop when block returns this value.
cursor_name: string   - Allows you to name your cursor.

Example:

Post.where(user_id:123).each_row { |hash| Post.process(hash) }
Post.each_row.map {|r| r["id"].to_i }

Returns the number of rows yielded to the block


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# File 'lib/postgresql_cursor/active_record/relation/cursor_iterators.rb', line 24

def each_row(options={}, &block)
  options = {:connection => self.connection}.merge(options)
  cursor  = PostgreSQLCursor::Cursor.new(to_unprepared_sql, options)
  return cursor.each_row(&block) if block_given?
  cursor
end

#each_row_batch(options = {}, &block) ⇒ Object Also known as: each_hash_batch

Public: Executes the query, yielding each batch of up to block_size rows where each row is a hash to the given block.

Parameters: same as each_row

Example:

Post.where(user_id:123).each_row_batch do |batch|
  Post.process_batch(batch)
end
Post.each_row_batch.map { |batch| Post.transform_batch(batch) }

Returns the number of rows yielded to the block


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# File 'lib/postgresql_cursor/active_record/relation/cursor_iterators.rb', line 60

def each_row_batch(options={}, &block)
  options = {:connection => self.connection}.merge(options)
  cursor  = PostgreSQLCursor::Cursor.new(to_unprepared_sql, options)
  return cursor.each_row_batch(&block) if block_given?
  cursor.iterate_batched
end

#pluck_instances(*cols) ⇒ Object Also known as: pluck_instance

Plucks the column names from the instances, and return them in an array


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# File 'lib/postgresql_cursor/active_record/relation/cursor_iterators.rb', line 98

def pluck_instances(*cols)
  options = cols.last.is_a?(Hash) ? cols.pop : {}
  options[:connection] = self.connection
  self.each_instance(options).pluck(*cols)
end

#pluck_rows(*cols) ⇒ Object Also known as: pluck_row

Plucks the column names from the rows, and return them in an array


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# File 'lib/postgresql_cursor/active_record/relation/cursor_iterators.rb', line 90

def pluck_rows(*cols)
  options = cols.last.is_a?(Hash) ? cols.pop : {}
  options[:connection] = self.connection
  self.each_row(options).pluck(*cols)
end