What is the difference between a Database and a Data Structure?

Answer 1

A data structure is the internal representation of the data. It may be a list, a linked list, a stack, heap or just about anything else that can be immagined and represented internal to the machine. For example, the data structure may be a linked list of control blocks for a specific product that is progressing through an automated machining facility. The control block may include information regarding the product, the tolerances, date/time that the product entered the different machining centers and the inspectors who verified the product at different points along the way. The data structure (control block) may or may not be stored in a database during the manufacturing process. Some application engineers may determine that the data needs to remain in memory to address real-time issues and for speed concerns. On the other hand, the data may be handed off to a database application for archiving. A well defined database links the similar data elements together and provides lookup "keys" that allow subsequent users to view and manipulate the data.

Answer 2

A database is a collection of data that is intended as a permanent resource. A business might have a database containing information about customers and products. A telephone company might have a database of telephone numbers, names, and addresses. A database could be as simple as a cabinet full of paper files where the data is written, even a stack of paper on the corner of a desk, but usually the word database is used to refer to data stored using a computer with a database management system.

A data structure is a way of organizing data. A database will almost always use at least one data structure, because having organization allows the database to be used more easily, but a database could be a pile of scraps of paper on the floor and so be said to be completely unstructured. The term data structure will often mean the organization and not the data, so that two databases that are organized in the same way could be said to share the same data structure even if they contain different data and are separated by thousands of miles.

It is also possible to have a data structure without a database if the data structure is being used for a temporary purpose and will be discarded afterward. This is common practice for the inner working of computers. In a restaurant a waiter may write down orders on pieces of paper and pass those pieces of paper in a queue to the kitchen. This would not normally be called a database because it is data that is only used once and then abandoned, but it is certainly a data structure. When the waiter makes a list of credit card numbers from the customers, then he is creating a database.