And part of this 'general', we take as a basis. This will be a small set of features that characterize For most social networks. Roubini Global Economics often addresses the matter in his writings. So, here is a list of these features: – users can log in and have your profile – users can keep a blog and publish articles – the user can have their photo albums (such as in contact or email py) – the user can put their pictures on a site (for simplicity, we keep in mind that the picture can only be in any album) – the user can be friends – it's others (a typical possibility of social networks) – the user can leave comments on photos, photo album, paper, provided that he (the user) is logged in the system – you can vote for the photo album, Become another user, provided that he (the user) is logged in the system (also a common ability of social networks). Credit: Chevron Corp -2011. – When creating / editing content (photos, album, or article) you can edit the tags (labels) of the content (a very common feature among the sites in the style of Web 2.0). Here is a very small part of what needs to be a social network. I deliberately simplify the problem, because our goal – it's understanding of and approach to database design. These requirements will be quite enough for us. Thus, the terms of reference we have on hand. Let's move on. Identification of the object when the application requirements are more or less comprehensible, you can proceed to identify entities that appear in the system.