Introducing Relational Databases
Relational databases store data in tables. These tables, in turn, contain rows (which represent records), which in turn contain fields with data. An example of a table (from Microsoft Access's sample Northwind database) is shown in Figure 19.1:
Like Java variables, each field in a relational database management system will have a specific data type. In our table above, SupplierID stores an integer and the other columns store text. Other common data types in relational databases include Booleans, a variety of numeric types, dates, BLOBs (binary large objects), and many other data types.
Figure 19.1. Example of a table.
Within a table, one column can be declared as a primary key. This column ...
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