I read professional_asp.net_design_patterns that contains real example that is much necessary for any developer. Also I read some topics of Head First Design pattern also fantastic book. If you are in .net framework I will suggest you to read professional_asp.net_design_patterns and Agile software development: principles, patterns and Practice in C#. Both of them are awesome for read. Both of them contains huge real example that will be helpful for you. professional_asp.net_design_patterns contains some most used GOF design patterns with examples and PER (Patterns of Enterprise Architecture) patterns example with SOLID Principles. I think this will be much better for you.

Mojam

I thinks second option is better than first option. Store all category specification in single table.

Mojam

Here are some Link With book name (1)Head First design pattern: http://www.amazon.com/First-Design-Patterns-Elisabeth-Freeman/dp/0596007124 Design Patterns CD: Elements of Reusable Object-Oriented Software: http://www.amazon.com/Design-Patterns-Object-Oriented-Professional-Computing/dp/0201634988 Agile Principles, Patterns, and Practices in C#: http://www.amazon.com/Agile-Principles-Patterns-Practices-C/dp/0131857258 Professional Asp.net Design Patterns: http://www.wrox.com/WileyCDA/WroxTitle/productCd-0470292784.html Patterns of Enterprise Application Architecture: http://www.amazon.com/Patterns-Enterprise-Application-Architecture-Martin/dp/0321127420

Mojam