Adding a Primary Key

[zambotinii]

I am using MySQL Front, and have created databases in the past.

 

However on this occasion I am having trouble creating a primary key. The MySQL Front program isnt giving me the option to make on of my columns a primary key and everytime I use the

 

ALTER TABLE table

ADD PRIMARY KEY (loginName);

 

command it reutrns an \"ERROR 1064\" message back.

 

Im sure Im logged in correctly but think this may eb the source of the problem! Any suggestions?

 

How would you make a field a PK in a table?