How to default database value when system date change
===

I'm currently doing a banking website for my project, using C# and asp.net. One of the function is 'Remaining Daily Limit'. I need the database value to change back to default once I changed the system date to another day. Example : If a user had $500 (default value) as a daily limit, and he used all up. The next day, he will have $500 again. May I know how should I go about it? 