PostgreSQL:
<insert id="insertUser">
		<selectKey keyProperty="uid" resultClass="long">
		 select nextval('fuser_uid_seq') as uid
		</selectKey>
		INSERT INTO fuser ( uid,username,fullname,admin,active ) 
			VALUES (#uid#,#username#,#fullname#,#admin#,#active# )
</insert>
Derby (auto-increment column):
  <insert id="insertUser">
    INSERT INTO fuser (username,fullname,admin,active )
      VALUES (#username#,#fullname#,#admin#,#active# )
    <selectKey keyProperty="uid" resultClass="long">
     values IDENTITY_VAL_LOCAL()
    </selectKey>
   </insert>