I am working on a database for a restaurant to keep track of certificates that it receives from its vendors. The certificates contain different lines of business (insurance) that have policy start/end dates (typical policy is 1 year term). I need to develop a database to store and track the certificates on file for each vendor and run lists of certificate that have a line of business that expires within the next 30 days, and a list of those that have expired. I am having trouble conceiving of what my tables should be...other than the fact that I know that I will have a table for vendors with a primary key of vendorID....I don't know how to approach the certificate best so that I can achieve what I need. Again, the certificate comes from a vendor...it lists lines of insurance (General Liability, Auto, Workers Compensation, etc.) and each line of business for each certificate has a start/end date. If one line of insurance expires then the restaurant needs an entire new certificate from the vendor. I will also need to store the historical/expired certificates for archival purposes so I presume I will need something like an active/inactive attribute on my certificate table so they do not get included in my expired reports. Any ideas or suggestions are greatly appreciated. I am new to database design.