class Arel::Visitors::Oracle
Private Instance Methods
order_hacks(o, a)
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Hacks for the order clauses specific to Oracle
# File lib/arel/visitors/oracle.rb, line 82 def order_hacks o, a return o if o.orders.empty? return o unless o.cores.any? do |core| core.projections.any? do |projection| /FIRST_VALUE/ === projection end end # Previous version with join and split broke ORDER BY clause # if it contained functions with several arguments (separated by ','). # # orders = o.orders.map { |x| visit x, a }.join(', ').split(',') orders = o.orders.map do |x| string = visit x, a if string.include?(',') split_order_string(string) else string end end.flatten o.orders = [] orders.each_with_index do |order, i| o.orders << Nodes::SqlLiteral.new("alias_#{i}__#{' DESC' if /\bdesc$/i === order}") end o end
split_order_string(string)
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Split string by commas but count opening and closing brackets and ignore commas inside brackets.
# File lib/arel/visitors/oracle.rb, line 111 def split_order_string(string) array = [] i = 0 string.split(',').each do |part| if array[i] array[i] << ',' << part else # to ensure that array[i] will be String and not Arel::Nodes::SqlLiteral array[i] = '' << part end i += 1 if array[i].count('(') == array[i].count(')') end array end
visit_Arel_Nodes_Except(o, a)
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# File lib/arel/visitors/oracle.rb, line 64 def visit_Arel_Nodes_Except o, a "( #{visit o.left, a} MINUS #{visit o.right, a} )" end
visit_Arel_Nodes_Limit(o, a)
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# File lib/arel/visitors/oracle.rb, line 57 def visit_Arel_Nodes_Limit o, a end
visit_Arel_Nodes_Offset(o, a)
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# File lib/arel/visitors/oracle.rb, line 60 def visit_Arel_Nodes_Offset o, a "raw_rnum_ > #{visit o.expr, a}" end
visit_Arel_Nodes_SelectStatement(o, a)
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Calls superclass method
Arel::Visitors::ToSql#visit_Arel_Nodes_SelectStatement
# File lib/arel/visitors/oracle.rb, line 6 def visit_Arel_Nodes_SelectStatement o, a o = order_hacks(o, a) # if need to select first records without ORDER BY and GROUP BY and without DISTINCT # then can use simple ROWNUM in WHERE clause if o.limit && o.orders.empty? && !o.offset && o.cores.first.set_quantifier.class.to_s !~ /Distinct/ o.cores.last.wheres.push Nodes::LessThanOrEqual.new( Nodes::SqlLiteral.new('ROWNUM'), o.limit.expr ) return super end if o.limit && o.offset o = o.dup limit = o.limit.expr.to_i offset = o.offset o.offset = nil sql = super(o, a) return <<-eosql SELECT * FROM ( SELECT raw_sql_.*, rownum raw_rnum_ FROM (#{sql}) raw_sql_ WHERE rownum <= #{offset.expr.to_i + limit} ) WHERE #{visit offset, a} eosql end if o.limit o = o.dup limit = o.limit.expr return "SELECT * FROM (#{super(o, a)}) WHERE ROWNUM <= #{visit limit, a}" end if o.offset o = o.dup offset = o.offset o.offset = nil sql = super(o, a) return <<-eosql SELECT * FROM ( SELECT raw_sql_.*, rownum raw_rnum_ FROM (#{sql}) raw_sql_ ) WHERE #{visit offset, a} eosql end super end
visit_Arel_Nodes_UpdateStatement(o, a)
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Calls superclass method
Arel::Visitors::ToSql#visit_Arel_Nodes_UpdateStatement
# File lib/arel/visitors/oracle.rb, line 68 def visit_Arel_Nodes_UpdateStatement o, a # Oracle does not allow ORDER BY/LIMIT in UPDATEs. if o.orders.any? && o.limit.nil? # However, there is no harm in silently eating the ORDER BY clause if no LIMIT has been provided, # otherwise let the user deal with the error o = o.dup o.orders = [] end super end