Relational databases serve as one of the most commonly used data sources in enterprise applications. Querying them requires the use of a different language altogether, such as the Structured Query Language (SQL). Let’s assume the same data as shown earlier exists in a relational database (for example, stored in SQL Server). Figure 19.1 illustrates what the records in a Products table might look like. Notice the presence of foreign keys in other tables (for example, to relate a product to a category).
Figure 19.1. A table in a relational database.
The command at the top of the screenshot is a SQL
SELECT statement used to retrieve ...