Forum: Ruby Time out of range when selecting from database?

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rm_rails (Guest)
on 2005-11-14 20:17
(Received via mailing list)
Why does Time allow such a limited set of years:

    irb> Time.mktime('2205-01-01')
    ArgumentError: time out of range

This especially annoying when other classes like DBI use
the Time class, and when a 200-year-lease in a database
throws an exception when loaded by Ruby.

irb(main):028:0> dbh.select_all("select begin_date,end_date from
leases")
ArgumentError: time out of range
         from /usr/lib/ruby/site_ruby/1.8/dbi/sql.rb:60:in `gm'
         from /usr/lib/ruby/site_ruby/1.8/dbi/sql.rb:60:in
`as_timestamp'
         from /usr/lib/ruby/site_ruby/1.8/DBD/Pg/Pg.rb:777:in
`as_timestamp'
         from /usr/lib/ruby/site_ruby/1.8/dbi/sql.rb:80:in `coerce'
         from /usr/lib/ruby/site_ruby/1.8/DBD/Pg/Pg.rb:395:in `convert'
         from /usr/lib/ruby/site_ruby/1.8/DBD/Pg/Pg.rb:755:in
`fill_array'
         from (irb):28:in `each_with_index'
         from /usr/lib/ruby/site_ruby/1.8/DBD/Pg/Pg.rb:754:in
`fill_array'
         from /usr/lib/ruby/site_ruby/1.8/DBD/Pg/Pg.rb:707:in `fetchrow'
         from /usr/lib/ruby/site_ruby/1.8/DBD/Pg/Pg.rb:644:in `fetch'
         from /usr/lib/ruby/site_ruby/1.8/dbi/dbi.rb:1155:in `fetch_all'
         from /usr/lib/ruby/site_ruby/1.8/dbi/dbi.rb:1154:in `fetch_all'
         from /usr/lib/ruby/site_ruby/1.8/dbi/dbi.rb:919:in `fetch_all'
         from /usr/lib/ruby/site_ruby/1.8/dbi/dbi.rb:675:in `select_all'
         from /usr/lib/ruby/site_ruby/1.8/dbi/dbi.rb:645:in `execute'
         from /usr/lib/ruby/site_ruby/1.8/dbi/dbi.rb:671:in `select_all'
         from (irb):28irb(main):029:0>

Surely if ruby can transparently do math between Fixnum's and Bignum's,
it could handle transparent math outside the range of the Time class,
can't it?
khaines (Guest)
on 2005-11-14 21:20
(Received via mailing list)
On Monday 14 November 2005 11:16 am, Ron M wrote:
> Why does Time allow such a limited set of years:
>
>     irb> Time.mktime('2205-01-01')
>     ArgumentError: time out of range
>
> This especially annoying when other classes like DBI use
> the Time class, and when a 200-year-lease in a database
> throws an exception when loaded by Ruby.

See the discussion about converting between Time and DateTime.  Time
uses
seconds since the start of 1970, and basically just uses the underlying
C
functions for most of what it does.  So, you are pretty limited in your
date
range.  Within the range supported, Time is fast because it uses a
simple
unit and C functions underneath, but that loses flexibility.

DateTime uses the Rational class, and can handle whatever date you want
to
give it.  It is a lot slower than Time, though.

Now, for DBI, there are a few issues with DBI currently with regard to
dates.
One of them is what you are describing.  DBI actually stores dates
internally
in one of three different classes, and internally it stores years,
months,
dates, hours, minutes, seconds separately, so it'll support any date
that you
want.  But the code that creates a DBI::Timestamp for you uses the Time
class, which is where your error came from.

A patch for DBI to to deal with this gracefully looks like it should not
be
too hard, though.  I'll see if I can whip one up sometime in the next
day or
two.


Kirk H.
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