fix terms_relationships database table duplicate obejct_ids

hi guys,

as it looks like a old developement server “forgot” on phpmyadmin mysql export to set some database table unique and auto increment keys. most of them i could fix.

all these tables don’t contain duplicate entries on unique column:
wp_posts
wp_postmeta
wp_terms
wp_termmeta
wp_term_taxonomy

but 1 table is pretty messed, and i guess that’s also the reason for endless media search and really bad performing speed: wp_terms_relationships got no unique column and no auto increment. e’ve been working on the mirrored site for 3 weeks now without discovering the root error.

there’s a total of 20k entries in that table. the table contains 750 duplicate object_id entries, each one between 2 and 38 times.

there is no way to set auto increment and unique column in phpmyadmin before fixing this.

i already tried just to make the object_id unique in libre office calc and then reimport. which messed up everthing as e.g. the nav menu entries seem to be referenced by object_id.

my questions:

is there any way to fix this without losing the past 3 weeks of work?

where does wordpress use the object_id column? pretty often in many places as it looks like.

any way to rebuild the terms_relationships table? the other terms tables look fine…