Re: [Ruby-DBI-devel] RFC: StatementHandle#execute

[Paul D. <pa...@sn...>]

At 15:07 +0100 3/31/03, Brian Candler wrote:
>I was writing some code like this:
>
>     s = db.prepare("select bar from foo where baz=?")
>     ...
>(1)
>     s.execute(key) do |sth|
>       result = sth.fetch
>     end
>
>Unfortunately, I discovered that it doesn't work like that - the block is
>simply ignored.

Right.  execute takes a block for a database handle, not a statement
handle.  Example:

dbh.execute("SHOW DATABASES") do |sth|
     sth.fetch do |row|
         puts row[0]
     end
end

>  It also doesn't work like this:
>
>(2)
>     t = s.execute(key)
>     result = t.fetch
>
>After some poking around, it turns out that when you run 'execute' on a
>StatementHandle it returns an empty DBI::Row object. You have to do:
>
>(3)
>     s.execute(key)
>     result = s.fetch
>
>I think it would be nice to support the block format as in (1), which I
>think would only need 'yield self if block_given?' in the execute method.
>
>I think it would also be nice to return self rather than the empty DBI::Row,
>so that you can chain execute with other operations:
>
>     result = s.execute(key).fetch
>
>What does anyone else think? It ought to be a simple change (the attached
>patch is untested though, as I need my app to work with the current API
>anyway)
>
>Regards,
>
>Brian.
>
>--- dbi.rb.orig Mon Mar 31 15:04:37 2003
>+++ dbi.rb      Mon Mar 31 15:05:23 2003
>@@ -747,6 +747,11 @@
>      #if @row.nil?
>        @row = DBI::Row.new(column_names,nil)
>      #end
>+    if block_given?
>+      yield self
>+    else
>+      self
>+    end
>    end
>
>    def finish