For example, renaming a database file does not rename the tables stored within it. This separation means that database administrators can manage physical data storage without affecting access to that data as a logical structure. The relational model means that the logical data structures-the data tables, views, and indexes-are separate from the physical storage structures. The warehouse can then pull the correct product, the customer can receive timely delivery of the order, and the company can get paid. Then, when the company’s order processing application submits an order to the database, the database can go to the customer order table, pull the correct information about the product order, and use the customer ID from that table to look up the customer’s billing and shipping information in the customer info table. But because of that common column, the relational database can create a relationship between the two tables. These two tables have only one thing in common: the ID column (the key). In the second table-a customer order table-each record includes the ID of the customer that placed the order, the product ordered, the quantity, the selected size and color, and so on-but not the customer’s name or contact information. Each bit of information (each attribute) is in its own column, and the database assigns a unique ID (a key) to each row.

The first table is a customer info table, so each record includes a customer’s name, address, shipping and billing information, phone number, and other contact information. Here’s a simple example of two tables a small business might use to process orders for its products.

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