Class: Arel::SelectManager

Inherits:
TreeManager show all
Includes:
Crud
Defined in:
lib/arel/select_manager.rb

Defined Under Namespace

Classes: Row

Constant Summary collapse

STRING_OR_SYMBOL_CLASS = 
[Symbol, String]

Instance Attribute Summary

Attributes inherited from TreeManager

#ast, #bind_values, #engine

Instance Method Summary collapse

Methods included from Crud

#compile_delete, #compile_insert, #compile_update, #create_insert

Methods inherited from TreeManager

#to_dot, #to_sql, #where

Methods included from FactoryMethods

#create_and, #create_false, #create_join, #create_on, #create_string_join, #create_table_alias, #create_true, #grouping, #lower

Constructor Details

#initialize(table = nil) ⇒ SelectManager

Returns a new instance of SelectManager.



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# File 'lib/arel/select_manager.rb', line 10

def initialize table = nil
  super()
  @ast   = Nodes::SelectStatement.new
  @ctx    = @ast.cores.last
  from table
end

Instance Method Details

#as(other) ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 51

def as other
  create_table_alias grouping(@ast), Nodes::SqlLiteral.new(other)
end

#constraints ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 27

def constraints
  @ctx.wheres
end

#distinct(value = true) ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 150

def distinct(value = true)
  if value
    @ctx.set_quantifier = Arel::Nodes::Distinct.new
  else
    @ctx.set_quantifier = nil
  end
  self
end

#distinct_on(value) ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 159

def distinct_on(value)
  if value
    @ctx.set_quantifier = Arel::Nodes::DistinctOn.new(value)
  else
    @ctx.set_quantifier = nil
  end
  self
end

#except(other) ⇒ Object Also known as: minus 



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# File 'lib/arel/select_manager.rb', line 202

def except other
  Nodes::Except.new ast, other.ast
end

#exists ⇒ Object

Produces an Arel::Nodes::Exists node



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# File 'lib/arel/select_manager.rb', line 47

def exists
  Arel::Nodes::Exists.new @ast
end

#from(table) ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 88

def from table
  table = Nodes::SqlLiteral.new(table) if String === table

  case table
  when Nodes::Join
    @ctx.source.right << table
  else
    @ctx.source.left = table
  end

  self
end

#froms ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 101

def froms
  @ast.cores.map { |x| x.from }.compact
end

#group(*columns) ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 77

def group *columns
  columns.each do |column|
    # FIXME: backwards compat
    column = Nodes::SqlLiteral.new(column) if String === column
    column = Nodes::SqlLiteral.new(column.to_s) if Symbol === column

    @ctx.groups.push Nodes::Group.new column
  end
  self
end

#having(expr) ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 122

def having expr
  @ctx.havings << expr
  self
end

#initialize_copy(other) ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 17

def initialize_copy other
  super
  @ctx = @ast.cores.last
end

#intersect(other) ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 198

def intersect other
  Nodes::Intersect.new ast, other.ast
end

#join(relation, klass = Nodes::InnerJoin) ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 105

def join relation, klass = Nodes::InnerJoin
  return self unless relation

  case relation
  when String, Nodes::SqlLiteral
    raise EmptyJoinError if relation.empty?
    klass = Nodes::StringJoin
  end

  @ctx.source.right << create_join(relation, nil, klass)
  self
end

#join_sources ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 230

def join_sources
  @ctx.source.right
end

#limit ⇒ Object Also known as: taken 



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# File 'lib/arel/select_manager.rb', line 22

def limit
  @ast.limit && @ast.limit.expr
end

#lock(locking = Arel.sql('FOR UPDATE')) ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 55

def lock locking = Arel.sql('FOR UPDATE')
  case locking
  when true
    locking = Arel.sql('FOR UPDATE')
  when Arel::Nodes::SqlLiteral
  when String
    locking = Arel.sql locking
  end

  @ast.lock = Nodes::Lock.new(locking)
  self
end

#locked ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 68

def locked
  @ast.lock
end

#offset ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 31

def offset
  @ast.offset && @ast.offset.expr
end

#on(*exprs) ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 72

def on *exprs
  @ctx.source.right.last.right = Nodes::On.new(collapse(exprs))
  self
end

#order(*expr) ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 168

def order *expr
  # FIXME: We SHOULD NOT be converting these to SqlLiteral automatically
  @ast.orders.concat expr.map { |x|
    STRING_OR_SYMBOL_CLASS.include?(x.class) ? Nodes::SqlLiteral.new(x.to_s) : x
  }
  self
end

#orders ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 176

def orders
  @ast.orders
end

#outer_join(relation) ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 118

def outer_join relation
  join(relation, Nodes::OuterJoin)
end

#project(*projections) ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 133

def project *projections
  # FIXME: converting these to SQLLiterals is probably not good, but
  # rails tests require it.
  @ctx.projections.concat projections.map { |x|
    STRING_OR_SYMBOL_CLASS.include?(x.class) ? Nodes::SqlLiteral.new(x.to_s) : x
  }
  self
end

#projections ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 142

def projections
  @ctx.projections
end

#projections=(projections) ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 146

def projections= projections
  @ctx.projections = projections
end

#skip(amount) ⇒ Object Also known as: offset= 



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# File 'lib/arel/select_manager.rb', line 35

def skip amount
  if amount
    @ast.offset = Nodes::Offset.new(amount)
  else
    @ast.offset = nil
  end
  self
end

#source ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 234

def source
  @ctx.source
end

#take(limit) ⇒ Object Also known as: limit= 



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# File 'lib/arel/select_manager.rb', line 218

def take limit
  if limit
    @ast.limit = Nodes::Limit.new(limit)
    @ctx.top   = Nodes::Top.new(limit)
  else
    @ast.limit = nil
    @ctx.top   = nil
  end
  self
end

#union(operation, other = nil) ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 187

def union operation, other = nil
  if other
    node_class = Nodes.const_get("Union#{operation.to_s.capitalize}")
  else
    other = operation
    node_class = Nodes::Union
  end

  node_class.new self.ast, other.ast
end

#where_sql(engine = Table.engine) ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 180

def where_sql engine = Table.engine
  return if @ctx.wheres.empty?

  viz = Visitors::WhereSql.new(engine.connection.visitor, engine.connection)
  Nodes::SqlLiteral.new viz.accept(@ctx, Collectors::SQLString.new).value
end

#window(name) ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 127

def window name
  window = Nodes::NamedWindow.new(name)
  @ctx.windows.push window
  window
end

#with(*subqueries) ⇒ Object 



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# File 'lib/arel/select_manager.rb', line 207

def with *subqueries
  if subqueries.first.is_a? Symbol
    node_class = Nodes.const_get("With#{subqueries.shift.to_s.capitalize}")
  else
    node_class = Nodes::With
  end
  @ast.with = node_class.new(subqueries.flatten)

  self
end