On 11 Jul 2006 16:33:50 -0700, "Qiangning Hong" <hongqn...gmail.com>
declaimed the following in comp.lang.python:
> I believe this will be faster than making the "url" column unique key
> and doing string comparation. Right?
>Given that the queries pass the data as strings, you're trading an
integer->string, string->integer conversion pair on each search,
followed by an index file look-up, for a straight index file look-up.
Granted, my college days were a quarter century ago, but at the
time, the data structures class required implementing a hash table
look-up program (hashed-head, multiple-linked list). Hashes weren't
guaranteed to be unique -- the hash only gave an entry point from which
one then performed string comparisons. *
You could maybe use MD5 encoding if you don't want the pure URL in
the look-up, and MySQL, at least, has a built-in for MD5 so you wouldn't
even have to worry about "differences".
* The Amiga file-system was a hashed-head, multiple-linked list -- the
only place I'd ever encountered one outside of that 3rd year college
course. File-names were hashed into an index into a directory block; the
directory block had pointers to file-header/subdirectory blocks... those
blocks then had a linked list to other fh/sd blocks that shared the hash
value.
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