Method: Sequel::Oracle::DatasetMethods#select_sql

Defined in:
lib/sequel/adapters/shared/oracle.rb

#select_sql ⇒ Object

Handle LIMIT by using a unlimited subselect filtered with ROWNUM, unless Oracle 12 is used.



414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
 
# File 'lib/sequel/adapters/shared/oracle.rb', line 414

def select_sql
  return super if @opts[:sql]
  return super if supports_fetch_next_rows?

  o = @opts[:offset]
  if o && o != 0
    columns = clone(:append_sql=>String.new, :placeholder_literal_null=>true).columns
    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 = unlimited
    # 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