Error on importing database -- 1.7

[Vee.K727]

I exported the database of my PS 1.7 installation as I was about to do some questionable things to the database. The said questionable things didn't turn  out well so I decided to restore my backup. I dropped all tables and imported the file but it gave me an error towards the end of the file.

 

This is where the errors occurred:

ALTER TABLE `ps_attribute`
  ADD PRIMARY KEY (`id_attribute`),  ADD KEY `IDX_6C3355F967A664FB` (`id_attribute_group`);

 

And this was the error:

#1068 - Multiple primary key defined

Isn't it an error? The database is trying to define multiple primary keys. is it safe if I skip all the ALTER TABLE queries after it as I already have imported the data?