Author: Alexey Makhotkin <squadette@gmail.com> (Word count: 2900). Foreign keys are one topic that you cannot ignore if you want to talk about database design. In this informational two-pager I’d like to point out the following aspects of foreign key technology: foreign keys are only a partial solution to the problem of database consistency; in classic relational databases, eliminating foreign keys may be an easy performance win; in many real-world scenarios foreign keys could not be enforced even if the underlying database supports them; This text is a complementary chapter of “Database Design Book” https://databasedesignbook.

Author: Alexey Makhotkin squadette@gmail.com. (Word count: 3200). A common problem in business-oriented database design: keeping the history of values of a certain data attribute. For example, we may want to track the price of various goods, as they change with time. Many other tasks could be reduced to this problem: for example, when people change their address in the government database, we may want to keep track of previous addresses.

Author: Alexey Makhotkin squadette@gmail.com. I wanted to demonstrate the relationship between the logical model and a physical model. We’re going to design a commonly seen use case: many yes/no attributes of a single anchor (in our case, Restaurant). Then we’ll discuss how the physical tables would be designed. We’ll see that sometimes physical design strategy changes as the system becomes more mature. At the same time, logical design elements never change if the business requirement is still relevant.