Gregory Seidman
3/24/2008 4:08:00 PM
On Tue, Mar 25, 2008 at 12:55:02AM +0900, abc- wrote:
> after hours of reading and searching i can't get the solution
> code:
>
> require 'mysql'
[iterating twice through the same result set, expecting the rows twice]
> I get this result only if i add
>
> require 'mysql'
> my = Mysql.new("localhost", "user", "", "database")
> data = my.query("select * from books Limit 5")
> p "first time"
> data.each { |d| p d[0]}
> p "again"
> data = my.query("select * from books Limit 5") << ADDED
> data.each { |d| p d[0]}
>
> So i think thats not the rigth way - don't repeat yourself
The result set returned by the query is not an array of rows. It is an
interface to reading the results row by row without storing all of them in
memory at once. This means that as you iterate, it throws out the previous
row. If you want an array of rows, through which you can iterate
as often as you like, use this:
require 'mysql'
my = Mysql.new("localhost", "user", "", "database")
data = my.query("select * from books Limit 5").extend(Enumerable).to_a
# ...
> Thanks in advance
> DG
--Greg