Do database design must have ideas, the dependence of the individual tables of finishing well.
We talk about a small example can make you easily master the idea of design data tables and fields
Before creating tables and fields must first clear the dependencies between the tables
scenarios: for example, now we have to do a site's electricity supplier database
finishing well to design a table: the user information table, commodity information table, clearing the table.
PS: Please watch the shopping cart to think about its dependencies according to this example of replication, Wu Di believe that smart you will do out of
ideas:
we must first set the table does not depend on the field of other tables (this statement must be read, read again a few times, read far),
for example, user information and product information table does not need to rely on other tables, then we first set up the fields and maybe a table.
The settlement requires both rely on the user information page table and need to rely on product information table then we design it last.
Field in each table below (especially Jane is a special edition, just to help my friends organize your thoughts) Figure:
Table user information: 
Table commodity information:
I only went for a id, additional information on what commodities they need plus what field it. 
Finally, more complicated table settlement page: 
to set up a database of the general idea is the case, I did not quite understand friends can comment below and I will respond promptly, you do not understand the likely others did not understand, you say it after I return everyone understands it not Yoshiya?