confus with a simple problem

[karikamiya]

K, so i got a table:

 

 

+---------+----------+
| imageid | tag      |
+---------+----------+
|       1 | celestia |
|       1 | official |
|       1 | flying   |
|       2 | celestia |
|       2 | official |
|       2 | flying   |
+---------+----------+

 

it was going all ok until i noticed there were some duplicates of both rows

 

+---------+----------+
| imageid | tag      |
+---------+----------+
|       1 | celestia |
|       1 | celestia |  <<< BAD
+---------+----------+

 

How can i:

 

1) delete the shown duplicates

2) set the table to not allow a duplicate of both rows to be inserteds

 

im using mysql 5.5.9

 

[attachment deleted by admin]

[karikamiya]

fixed, manually removed the offenders and ran

 

ALTER TABLE `icidtags` ADD UNIQUE (`imageid`, `tag`);