Mod在谷歌索引上重写404

Question

my url is site.com/nl/url-rewrite/categorie-1
my mod rewrite rules are:

# Rewrite taxonomy URLs
#   Input:  LANG/url-rewrite/TERM
#   Output: url_rewrite.php?term=TERM
RewriteRule ^.{2}/url-rewrite/([A-Za-z0-9-]+)/?$ /url_rewrite.php?term=$1 [L]
#   Input:  LANG/url-rewrite
#   Output: url_rewrite.php
RewriteRule ^.{2}/url-rewrite/?$ /url_rewrite.php [L]

This works fine (not sure if the 2nd rule is the best way to approach this)

Now I'll get a link in google too site.com/nl/url-rewrite/categorie-1
'categorie-1' is the seo friendly alias of my category

If the title of my category changes too 'Categorie 2', my alias will be 'categorie-2' (auto alias)

this link in google site.com/nl/url-rewrite/categorie-1 will not work now
how can I solve this?
I used id's before, so my link would be site.com/nl/url-rewrite/1/categorie-1
But that doens't look so good, I don't want any id's in the url

Answer 1

When you change your titles you need to 301 redirect the old URL to the new URL. You can either do this by internally tracking this when you change and having the url_rewrite.php script redirect the browser to site.com/nl/url-rewrite/categorie-2 when it sees someone trying to access categorie-1 (because it knows it's been changed), or you can manually add (above the 2 rules that you have) rules to do the 301 redirect manually:

RedirectMatch 301 ^/?(.{2})/url-rewrite/categorie-1/?$ /$1/url-rewrite/categorie-2/

The 301 tells google that all of the link information associated with the categorie-1 link should be transfered over to the new categorie-2 link. You'll just have to wait for search engines to get around to re-indexing the old links before that transfer happens so your pages will still show up as 404 until then.