Class: Arel::Visitors::Derby

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

Instance Method Summary collapse

Methods included from ArJdbcCompat

#limit_for

Instance Method Details

#visit_Arel_Nodes_Limit(o) ⇒ Object 



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# File 'lib/arel/visitors/derby.rb', line 16

def visit_Arel_Nodes_Limit o
  "FETCH FIRST #{limit_for(o)} ROWS ONLY"
end

#visit_Arel_Nodes_Lock(o) ⇒ 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 27

def visit_Arel_Nodes_Lock o
  visit o.expr
end

#visit_Arel_Nodes_Offset(o) ⇒ Object 



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# File 'lib/arel/visitors/derby.rb', line 20

def visit_Arel_Nodes_Offset o
  "OFFSET #{visit o.value} ROWS"
end

#visit_Arel_Nodes_SelectStatement(o) ⇒ Object 



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# File 'lib/arel/visitors/derby.rb', line 6

def visit_Arel_Nodes_SelectStatement o
  [
   o.cores.map { |x| visit(x) }.join,
   ("ORDER BY #{o.orders.map { |x| visit x }.join(', ')}" unless o.orders.empty?),
   (visit(o.offset) if o.offset),
   (visit(o.limit) if o.limit),
   (visit(o.lock) if o.lock),
  ].compact.join ' '
end