How do I set up a mySQL table structure for a business directory with many to many relationship?
I am trying to plan my table structure for a business directory where I will have multiple parent categories for multiple sub-categories and multiple business listings, all of which will require a many to many relationship.
eg.
A Night Out
Clubs and Societies
Public Houses Restaurants Taxis and Private Hire Vehicles Theatres and Concert Halls Wine BarsRestaurants
Chinese / Oriental
Bistros Fish and Chips Indian Italian Public Houses Seafood SpanishTransport and Carriers
Air Charter and Rental
Airlines Car / Van Hire Self Drive Courier and Distribution Services Estate / Property Re-location Services Freight Services and Agents Haulage Contractors Post Offices and Services Re-location Services Taxis and Private Hire Vehicles Van HireAs you can see, Restaurants is both a main category and a subcategory. Taxis and Private Hire Vehicles belongs to both Transport and Carriers and A Night Out and under all of these categories, on the lowest level, I will have the business listings. I will not be allowing businesses to submit their own listings but rather adding them myself upon request. A business listing can belong to a maximum of 6 categories.
I am struggling to find the best structur开发者_开发知识库e of tables for my database and would be very grateful for any suggestions. I am relatively new to php/mySQL.
You could have a category table which will contain a list of all possible categories/subcategories and then in your information table have it so that there is a CategoryID field as well as a SubCategoryID where you will either have NULL for the subcategory or the corresponding id.
You could also map it using a mapping table, that way you will be able to have as many categories / subcategories as you want.
Category Table ( CategoryId, CategoryName )
Business Table ( BusinessId, BusinessName )
Category Mapping Table ( BusinessId, CategoryId, IsCategory )
The IsCategory would be a BIT field so that you can mark any number of categories for a business as either a SubCategory (0) or a Category (1).
On the Category Mapping Table I would make the PRIMARY KEY ( BusinessId, CategoryId ) as well as make them FOREIGN KEYs to the Business / Category table respectively.
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