select count(*) from reader_card where reader_id = #{reader_id} and password = #{password} select * from reader_card where reader_id = #{reader_id} update reader_card set password = #{password} where reader_id = #{reader_id} select password from reader_card where reader_id = #{reader_id} insert into reader_card values (#{reader_id}, #{username}, #{password}) delete from reader_card where reader_id = #{reader_id}