MySQL Error: #1062 - Duplicate entry 'rewrite_rules' for key 2

I am trying to restore a WordPress MySQL DB from a recent backup since my site (wp-admin) became unusable after I changed the site_url incorrectly. I am trying to reinstall the entire site again but need to reinstall the DB. The 开发者_运维百科problem is my wp_options table will not upload via PHPmyAdmin. The error I get is:

#1062 - Duplicate entry 'rewrite_rules' for key 2

I know little about MySQL but this seems odd as the DB was working happily before I deleted it to attempt the reinstall.

Can anyone please advise?

The error means that you are inserting data into a column with must be unique.

In this case you may be importing data that has 'rewrite_rules' as a data item in a row into a table that already has 'rewrite_rules' as a data item in a row in a column that as been marked as unique.

If you are reinstalling wordpress from scratch and are trying to import the old data over the top you need to take a few steps first. See the link below for some instructions

http://www.ehow.com/how_4579080_export-import-wordpress-blog.html