Author: Chris Connolly


A database is a set of data held within a web-server or on a local hard drive which are designed to offer an organized mechanism for storing, managing and retrieving information.


They allow you to retrieve information/data through the use of tables. The collected information could be in any number of formats (electronic, printed, graphic, audio, statistical, combinations). There are physical (paper/print) and electronic databases.

Databases aren't just used for storing computational data. We have everyday usages for them as-well. If you purchase something at the grocery store, the price is being looked up in a database based on the UPC (Universal Product Code). When you make a phone call, a database is being accessed for information on how to route the call. Caller ID information is also looked up in a database. This web site runs on a database (as do most others).

Explanation and application

How do supermarkets utilise Databases?

A supermarket uses databases predominantly for their products. For example a supermarket would use a database for keeping track of inventory. They might also keep an inventory for all the customers or vendors that are supplying the inventories. If you think about all the items for sale in the supermarket they will all be stored in a database also; like the product names, description, quantity, price, supplier, etc...

Purchase History:
Some databases can track what you have bought, this can bring in ethical issues about data collation. However that isn't the point here... For example in England the Nectar database contains information about what Nectar cardholders buy at every retailer in the scheme. This makes it particularly adept at identifying and targeting customers according to their demographic profile. There would be tables set up for food, price, types of food or drink. Then there would be written conclusions that would state that if (condition) == True then offer this. For example if you have been buying a lot of baby milk, the database would recognize this and offer you discounts when available for baby milk. They use these marketing schemes within databases to convince you to shop with them.

The different types of Databases:

Introduced in the 1960s, these were the first databases. They maintained records and pointers between them but had no indexing or search.

These databases allow one to many relationships, as with an order and its line items. A record can be looked up using an index, speeding up searches.

A server-based database performs all data access in a separate process outside the application program, usually on a separate computer. The server program enforces data integrity rules, resulting in a more reliable database.

Some databases are complete application environments, including data management, programming languages and data entry forms.

How they work:

Just like Excel tables, database tables consist of columns and rows . Each column contains a different type of attribute and each row corresponds to a single record . For example, imagine that we were building a database table that contained names and telephone numbers. We’d probably set up columns named “FirstName”, “LastName” and “TelephoneNumber.” Then we’d simply start adding rows underneath those columns that contained the data we’re planning to store.

If we were building a table of contact information for our business that has 50 employees, we’d wind up with a table that contains 50 rows.

Why can’t I just use a spreadsheet like Microsoft Excel?

Databases are actually much more powerful than spreadsheets in the way you’re able to manipulate data. Here are just a few of the actions that you can perform on a database that would be difficult if not impossible to perform on a spreadsheet:
  • Retrieve all records that match certain criteria
  • Update records in bulk
  • Cross-reference records in different tables
  • Perform complex aggregate calculations

References and resources