Class: Devlin::Query

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

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(parent, q) ⇒ Query

Returns a new instance of Query.



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# File 'lib/devlin/query.rb', line 5

def initialize(parent, q)
  @parent = parent
  @query = YAML.load(q)
  @scope = parent.scope(query['scope'])
  @scope_name = query['scope']
  @select = query['select']
  @conditions = query['conditions']
  @group = query['group']
  @order = query['order']
end

Instance Attribute Details

#query ⇒ Object (readonly)

Returns the value of attribute query.



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

def query
  @query
end

#scope ⇒ Object (readonly)

Returns the value of attribute scope.



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

def scope
  @scope
end

#scope_name ⇒ Object (readonly)

Returns the value of attribute scope_name.



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

def scope_name
  @scope_name
end

Instance Method Details

#conditions ⇒ Object

def select



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# File 'lib/devlin/query.rb', line 49

def conditions
  @conditions || {}
end

#group ⇒ Object

def conditions



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

def group
  @group || []
end

#order ⇒ Object

def group



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# File 'lib/devlin/query.rb', line 57

def order
  res = {}
  (@order || {}).each do |key, value|
    res[key] = case value.to_s.downcase
               when 'desc'
                 'DESC'
               else
                 'ASC'
               end
  end
  res
end

#result ⇒ Object

This method returns the resulting relation to calculate the given query



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# File 'lib/devlin/query.rb', line 18

def result
  res = @scope.relation
  res = res.select(self.select.map { |c| @scope.column(c).select_definition })
  self.conditions.each do |col, val|
    col, op = col.split('.')
    res = case op
    when 'g'
      res.where(["#{@scope.column(col).definition}>?", val])
    when 'geq'
      res.where(["#{@scope.column(col).definition}>=?", val])
    when 'l'
      res.where(["#{@scope.column(col).definition}<?", val])
    when 'leq'
      res.where(["#{@scope.column(col).definition}<=?", val])
    when 'in'
      res.where(["#{@scope.column(col).definition} IN (?)", val])
    else
      res.where(["#{@scope.column(col).definition}=?", val])
    end
  end
  res = res.group(self.group.map { |c| @scope.column(c).definition })
  self.order.each do |col, val|
    res = res.order("#{@scope.column(col).definition} #{val}")
  end
  res
end

#select ⇒ Object

def result



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# File 'lib/devlin/query.rb', line 45

def select
  @select or raise "No selection columns given"
end