Class: Believer::Query

Inherits:
ScopedCommand show all
Defined in:
lib/believer/query.rb

Instance Attribute Summary collapse

Attributes inherited from ScopedCommand

#wheres

Instance Method Summary collapse

Methods inherited from ScopedCommand

#where

Methods inherited from Command

#clone, #connection, #execute

Constructor Details

#initialize(attrs) ⇒ Query 



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# File 'lib/believer/query.rb', line 8

def initialize(attrs)
  super
end

Instance Attribute Details

#limit_to ⇒ Object

Returns the value of attribute limit_to.



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# File 'lib/believer/query.rb', line 4

def limit_to
  @limit_to
end

#order_by ⇒ Object

Returns the value of attribute order_by.



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# File 'lib/believer/query.rb', line 4

def order_by
  @order_by
end

#record_class ⇒ Object

Returns the value of attribute record_class.



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# File 'lib/believer/query.rb', line 4

def record_class
  @record_class
end

#selects ⇒ Object

Returns the value of attribute selects.



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# File 'lib/believer/query.rb', line 4

def selects
  @selects
end

Instance Method Details

#[](index) ⇒ Object 



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# File 'lib/believer/query.rb', line 122

def [](index)
  to_a[index]
end

#count ⇒ Object 



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# File 'lib/believer/query.rb', line 104

def count
  count_q = clone
  count_q.selects = ['COUNT(*)']
  result = count_q.execute

  cnt = -1
  result.each do |row|
    cnt = row['count']
  end
  cnt
end

#delete_all(options = {}) ⇒ Object 



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# File 'lib/believer/query.rb', line 70

def delete_all(options = {})
  cnt = count
  chunk_size = options[:delete_batch_chunk_size] || (self.limit_to.nil? ? nil : self.limit_to.size) || cnt
  key_cols = self.record_class.primary_key_columns
  deleted_count = 0
  while deleted_count < cnt
    batch = Batch.new(:record_class => @record_class)
    rows_to_delete = clone.select(key_cols).limit(chunk_size).execute
    rows_to_delete.each do |row_to_delete|
      batch << Delete.new(:record_class => self.record_class).where(row_to_delete)
    end
    batch.execute
    deleted_count += batch.commands.size
  end
  deleted_count
end

#destroy_all ⇒ Object 



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# File 'lib/believer/query.rb', line 62

def destroy_all
  objects = to_a
  objects.each do |obj|
    obj.destroy
  end
  objects.size
end

#each ⇒ Object 



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# File 'lib/believer/query.rb', line 116

def each
  to_a.each do |r|
    yield r
  end
end

#first ⇒ Object 



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# File 'lib/believer/query.rb', line 126

def first
  return @result_rows.first unless @result_rows.nil?
  clone.limit(1)[0]
end

#last ⇒ Object 



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# File 'lib/believer/query.rb', line 131

def last
  return @result_rows.last unless @result_rows.nil?
  raise "Cannot retrieve last of no order column is set" if @order_by.nil?
  lq = clone.limit(1)
  lq.order_by = @order_by.inverse
  lq[0]
end

#limit(l) ⇒ Object 



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# File 'lib/believer/query.rb', line 32

def limit(l)
  q = clone
  q.limit_to = Limit.new(l)
  q
end

#order(field, order = :asc) ⇒ Object 



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# File 'lib/believer/query.rb', line 26

def order(field, order = :asc)
  q = clone
  q.order_by = OrderBy.new(field, order)
  q
end

#query_attributes ⇒ Object 



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# File 'lib/believer/query.rb', line 12

def query_attributes
  attrs = super
  attrs.merge(:order_by => @order_by, :selects => @selects, :limit_to => @limit_to)
end

#select(*fields) ⇒ Object 



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# File 'lib/believer/query.rb', line 17

def select(*fields)
  q = clone
  q.selects ||= []
  q.selects += fields
  q.selects.flatten!
  #puts "New selects: #{q.selects}, added: #{fields}"
  q
end

#size ⇒ Object 



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# File 'lib/believer/query.rb', line 100

def size
  to_a.size
end

#to_a ⇒ Object 



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# File 'lib/believer/query.rb', line 87

def to_a
  unless @result_rows
    result = execute
    @result_rows = []
    start = Time.now
    result.each do |row|
      @result_rows << @record_class.instantiate_from_result_rows(row)
    end
    puts "Took #{sprintf "%.3f", (Time.now - start)*1000.0} ms to deserialize #{@result_rows.size} object(s)"
  end
  @result_rows
end

#to_cql ⇒ Object 



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# File 'lib/believer/query.rb', line 46

def to_cql
  cql = "SELECT "
  if @selects && @selects.any?
    cql << "#{@selects.join(', ')}"
  else
    cql << @record_class.columns.keys.join(',')
    #cql << "*"
  end

  cql << " FROM #{@record_class.table_name}"
  cql << " WHERE #{@wheres.map { |wc| "#{wc.to_cql}" }.join(' AND ')}" if @wheres && @wheres.any?
  cql << " #{@order_by.to_cql}" unless @order_by.nil?
  cql << " #{@limit_to.to_cql}" unless @limit_to.nil?
  cql
end