php - Check Read and unread Message -

i trying conditionally style user-to-user messages on site based on following:

if user has not yet accessed message, remains bold ("unread"). if user clicks link , accesses it, goes bold unbold ("read")

(reference: how many email inboxes work)

question: how check if user has clicked on link view new message, or if have not? in, how store information , indicate has been "read"?

try adding column messages' table (for example read) , set column 1 when user has read message?