From the course: Learning Relational Databases
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Develop subtypes and supertypes
From the course: Learning Relational Databases
Develop subtypes and supertypes
- [Narrator] When you start combining your field list into table groupings, you might start to identify tables that share many characteristic fields, but then have a subset of fields that are specific to a particular business rule. For instance, let's suppose that the Two Trees Olive Oil Company caters to two distinct types of customers. Wholesale customers that resale our products, and retails customers that purchase from us directly. Both types of customers will have common fields, such as a customer ID number, address fields, and they would both be linked to an order history through an invoices table. But each type of customer also has specific attributes that are unique to their type of customer that they represent. Retail customers would have a first and last name, whereas a whole sale customer would have a company name. Further, you might have related information that only applies to one type of customer. The wholesale customers might have multiple regional sales…
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