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# frozen_string_literal: true
module Arel # :nodoc: all
module Visitors
class Oracle12 < Arel::Visitors::ToSql
private
def visit_Arel_Nodes_SelectStatement(o, collector)
# Oracle does not allow LIMIT clause with select for update
if o.limit && o.lock
raise ArgumentError, <<~MSG
Combination of limit and lock is not supported. Because generated SQL statements
`SELECT FOR UPDATE and FETCH FIRST n ROWS` generates ORA-02014.
MSG
end
super
end
def visit_Arel_Nodes_SelectOptions(o, collector)
collector = maybe_visit o.offset, collector
collector = maybe_visit o.limit, collector
maybe_visit o.lock, collector
end
def visit_Arel_Nodes_Limit(o, collector)
collector << "FETCH FIRST "
collector = visit o.expr, collector
collector << " ROWS ONLY"
end
def visit_Arel_Nodes_Offset(o, collector)
collector << "OFFSET "
visit o.expr, collector
collector << " ROWS"
end
def visit_Arel_Nodes_Except(o, collector)
collector << "( "
collector = infix_value o, collector, " MINUS "
collector << " )"
end
def visit_Arel_Nodes_UpdateStatement(o, collector)
# 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
def visit_Arel_Nodes_BindParam(o, collector)
collector.add_bind(o.value) { |i| ":a#{i}" }
end
def is_distinct_from(o, collector)
collector << "DECODE("
collector = visit [o.left, o.right, 0, 1], collector
collector << ")"
end
end
end
end
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