Module: Oracle::DatasetMethods

Defined in:
lib/engine2/post_bootstrap.rb

Instance Method Summary collapse

Instance Method Details

#select_sql ⇒ Object 



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# File 'lib/engine2/post_bootstrap.rb', line 53

def select_sql
  return super if @opts[:sql]
  if o = @opts[:offset]
    # columns = clone(:append_sql=>String.new, :placeholder_literal_null=>true).columns
    columns = SequelFixes.fix_aliased_expression(clone(:append_sql=>String.new, :placeholder_literal_null=>true))
    dsa1 = dataset_alias(1)
    rn = row_number_column
    limit = @opts[:limit]
    ds = unlimited.
      from_self(:alias=>dsa1).
      select_append(ROW_NUMBER_EXPRESSION.as(rn)).
      from_self(:alias=>dsa1).
      select(*columns).
      where(SQL::Identifier.new(rn) > o)
    ds = ds.where(SQL::Identifier.new(rn) <= Sequel.+(o, limit)) if limit
    sql = @opts[:append_sql] || String.new
    subselect_sql_append(sql, ds)
    sql
  elsif limit = @opts[:limit]
    ds = clone(:limit=>nil)
    # Lock doesn't work in subselects, so don't use a subselect when locking.
    # Don't use a subselect if custom SQL is used, as it breaks somethings.
    ds = ds.from_self unless @opts[:lock]
    sql = @opts[:append_sql] || String.new
    subselect_sql_append(sql, ds.where(SQL::ComplexExpression.new(:<=, ROW_NUMBER_EXPRESSION, limit)))
    sql
  else
    super
  end
end