verifying sql INSERTs

Hi! (MySQL) What's the best way to determine a sql INSERT statement has executed successfully? What I've got is a function whose sole purpose is to add new staff members to an app. I've written. There's a basic form that the user fills out (first name, last name, email address) and submits. Only one record per email address is allowed. Here is a pseudo code version of what I have right now. function insertStaffer($fname, $lname, $email) { $sql = "SELECT table WHERE email = '$email'"; if(1 or more records are found) { return 0; // means email address is already used } else { $sql = "INSERT INTO table ..."; return 1; // assume record inserted correctly } } Now for my question: Should I just assume the INSERT INTO has worked correctly (like I'm currently doing) and return a 1? Or should I verify that the INSERT worked correctly (by using the MySQL last_insert_id() function)? Alternatively... maybe the mysql_query() function returns a true/false status based on what happens? Hmm... I should look into that. I'd appreciate any advice you have to give. Thanks, Chris.