This is the fourth in our multi–part series on data modeling for information security as well as data characteristics. A simple data model for a fictional website that supports shared–interest organizations (bird–watching clubs, etc.) has provided us with content for exploring data modeling from a security viewpoint.In Oscar Wilde’s playLady Windermere’s Fan, Lord Darlington tags a cynic as “somebody who knows the price of everything, and the value of nothing.” Sadly, the information in our databases can be unconsciously treated in the same way. Is a customer account worth the sum of its purchases? What do we suffer if we lose four hours of marketing data during holiday shopping season?