Class: Rusql::Query

Inherits:
Object
  • Object
show all
Defined in:
lib/rusql/query.rb

Instance Method Summary collapse

Constructor Details

#initialize(selectors) ⇒ Query

Returns a new instance of Query.



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# File 'lib/rusql/query.rb', line 3

def initialize(selectors)
  selectors.each do |selector|
    raise TypeException.new(Selector, selector.class) unless selector.is_a?(Selector)
  end

  @selectors = selectors
  @joins = []
  @orders = []
end

Instance Method Details

#duplicate ⇒ Object 



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# File 'lib/rusql/query.rb', line 13

def duplicate
  new_one = Query.new(self.instance_variable_get(:@selectors))
  new_one.instance_variable_set( :@condition,  self.instance_variable_get(:@condition)  )
  new_one.instance_variable_set( :@from_table, self.instance_variable_get(:@from_table) )
  new_one.instance_variable_set( :@joins,      self.instance_variable_get(:@joins)      )
  new_one.instance_variable_set( :@limit,      self.instance_variable_get(:@limit)      )
  new_one.instance_variable_set( :@orders,     self.instance_variable_get(:@orders)     )

  new_one
end

#from(t) ⇒ Object

Raises:



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# File 'lib/rusql/query.rb', line 44

def from(t)
  raise TypeException.new(Table, t.class) unless t.is_a?(Table)

  new_one = self.duplicate
  new_one.instance_variable_set(:@from_table, t)

  new_one
end

#join(join) ⇒ Object

Raises:



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# File 'lib/rusql/query.rb', line 53

def join(join)
  raise TypeException.new(Join, join.class) unless join.is_a?(Join)

  new_one = self.duplicate
  joins = new_one.instance_variable_get(:@joins)
  joins << join
  new_one.instance_variable_set(:@joins, joins)

  new_one
end

#limit(c) ⇒ Object

Raises:



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# File 'lib/rusql/query.rb', line 35

def limit(c)
  raise TypeException.new(Fixnum, c.class) unless c.is_a?(Fixnum)

  new_one = self.duplicate
  new_one.instance_variable_set(:@limit, c)

  new_one
end

#order_by(*orders) ⇒ Object 



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# File 'lib/rusql/query.rb', line 84

def order_by(*orders)
  orders.each do |o|
    raise TypeException.new(Order, o.class) unless o.is_a?(Order)
  end

  new_one = self.duplicate
  new_one.instance_variable_set(:@orders, orders)

  new_one
end

#select(*selectors) ⇒ Object 



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# File 'lib/rusql/query.rb', line 24

def select(*selectors)
  selectors.each do |selector|
    raise TypeException.new(Selector, selector.class) unless selector.is_a?(Selector)
  end

  new_one = self.duplicate
  new_one.instance_variable_set(:@selectors, selectors)

  new_one
end

#to_s ⇒ Object 



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# File 'lib/rusql/query.rb', line 95

def to_s
  join_part = @joins.map{ |j| "\n#{j.to_s}" }.join
  where_part = "\nWHERE"
  order_part = "\nORDER BY #{ @orders.map(&:to_s).join(", ") }"

  if @condition.is_a?(BasicCondition)
    where_part += " "
    where_part += @condition.to_s
  elsif @condition.is_a?(ComplexCondition)
    where_part += "\n  "
    where_part += @condition.to_s
  end

  <<-EOS
SELECT
#{ @selectors.map{ |s| "  #{s.to_s}" }.join(",\n") }
FROM #{ @from_table.to_s_for_aliasing }#{ (@joins.length > 0) ? join_part : ""  }#{ @condition.nil? ? "" : where_part }#{ @orders.length > 0 ? order_part : "" }
  EOS
end

#where(condition) ⇒ Object

Raises:



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# File 'lib/rusql/query.rb', line 75

def where(condition)
  raise TypeException.new(Condition, condition.class) unless condition.is_a?(Condition)

  new_one = self.duplicate
  new_one.instance_variable_set(:@condition, condition)

  new_one
end