Class: Arel::Visitors::Derby

Inherits:
ToSql
  • Object
show all
Defined in:
lib/arel/visitors/derby.rb

Instance Method Summary collapse

Instance Method Details

#visit_Arel_Nodes_InsertStatement(o, a = nil) ⇒ Object

AR 4.0 ... AREL 5.0 since AR >= 4.1



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# File 'lib/arel/visitors/derby.rb', line 89

def visit_Arel_Nodes_InsertStatement o, a = nil
  a << "INSERT INTO "
  visit(o.relation, a)

  values = o.values

  if o.columns.any?
    cols = o.columns.map { |x| quote_column_name x.name }
    a << ' (' << cols.join(', ') << ') '
  elsif o.values.eql? VALUES_DEFAULT
    cols = o.relation.engine.columns.map { |c| c.name }
    a << ' (' << cols.join(', ') << ')'
    a << ' VALUES '
    a << ' (' << cols.map { 'DEFAULT' }.join(', ') << ')'
    values = false
  end
  visit(values, a) if values
  a
end

#visit_Arel_Nodes_Limit(o, a = nil) ⇒ Object 



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# File 'lib/arel/visitors/derby.rb', line 42

def visit_Arel_Nodes_Limit(o, a = nil)
  limit = "FETCH FIRST #{limit_for(o)} ROWS ONLY"
  a << limit if a
  limit
end

#visit_Arel_Nodes_Lock(o, a = nil) ⇒ Object

This generates SELECT...FOR UPDATE, but it will only work if the current transaction isolation level is set to SERIALIZABLE. Otherwise, locks aren't held for the entire transaction.



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# File 'lib/arel/visitors/derby.rb', line 61

def visit_Arel_Nodes_Lock o, a = nil
  do_visit o.expr, a
end

#visit_Arel_Nodes_Offset(o, a = nil) ⇒ Object 



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# File 'lib/arel/visitors/derby.rb', line 48

def visit_Arel_Nodes_Offset(o, a = nil)
  if a
    a << 'OFFSET '
    do_visit(o.value, a)
    a << ' ROWS'
  else
    "OFFSET #{do_visit o.value, a} ROWS"
  end
end

#visit_Arel_Nodes_SelectStatement(o, a = nil) ⇒ Object 



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# File 'lib/arel/visitors/derby.rb', line 11

def visit_Arel_Nodes_SelectStatement(o, a = nil)
  a = o.cores.inject(a) { |c, x| visit_Arel_Nodes_SelectCore(x, c) }
  unless o.orders.empty?
    a << ' ORDER BY '
    last = o.orders.length - 1
    o.orders.each_with_index do |x, i|
      visit(x, a);  a << ', ' unless last == i
    end
  end
  if o.offset
    a << STR_1; visit(o.offset, a)
  end
  if o.limit
    a << STR_1; visit(o.limit, a)
  end
  if o.lock
    a << STR_1; visit(o.lock, a)
  end
  a
end