Chapter 2. Database Design Essentials

A relational database is essentially just a set of tables of data that are related to each other. These tables are useful because we can use a high-level language, such as SQL, to add, change, or delete the tables or the data in the tables. We can query the database and obtain the results of selecting data based on simple or complex relations. We can perform set operations, such as joins, on the data. These capabilities let us store, manage, and make use of even very large amounts of data.

Tables can hold data of different types, allowing us to store, primarily, numbers, dates, and text. We can perform calculations, sort, or change these types of data. (There are also types used to store arbitrary data—which ...

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