i am writing a c# program where i want to get only a single row per day.the database just has 2 fields
now i want to retieve and display only 1 message in the textbox and the database should automatically get the next row as soon as the date changes

You should probably have a date field in the table, otherwise all you can do is assume a new record was added each day, and get the most recent.
Your question is a bit ambigious. Databases do not automatically get the next row, they store data. It is up to your application to poll the database for new data, or setup notification services (doesn't sound like you need to go down that path).
Without noting all the possible assumptions I can think of, maybe it would be better for you to provide a better description of what you are trying to do.

// Jerry

see its basically is a web application with c# code behind it,ok so after i add the date field what should i do so the web apllication automatically updates the content with data from the next row