The expression database refers to an archive of data, organised in order to allow the management of the data (insert, search, delete and update) using software applications.

The word “database” is often used informally and wrongly as an abbreviation of the formal expression “Database Management System”, that, instead, refers to the wide category of software systems that allows the user to create and manage databases in efficient ways. This serious mistake leads only to a big confusion where the content and its container/manager are mixed together.

It is common to visualize a database as a grid of data, where the rows represent the records and the columns the information fields. However this simple idea just applies to really simple databases.

A simple example of database is the address book: its management can starts with a data grid and can ends with a complex system where each item is broken up to its smallest parts in order to optimise the management and to maximized the scalability.

A database must store the data itself and the information about its representation and the relationships among them.

To speak about the database means:

1. to examine closely the information that must be managed
2. to study carefully the usage of the information
3. to design a logical scheme of the database
4. to select the proper DBMS
5. to design and implement the database into the selected DBMS
6. to design and implement the software application that will be used to manage the data stored in the database
7. to design and implement the software application that will allow the user to access the contents of the database

There are several kind of DBMS, that can be distinguished depending on the technology they adopt and the data handling method. Depending on the size and the usage of the database, MESI can use one of the following solutions:

• desktop DB
  • Microsoft Access
  • Microsoft Visual FoxPro
• open-source client-server DB
  • MySQL
  • PostgreSQL
• commercial client-server DB
  • Microsoft SQL Server
  • Oracle

There are circumstances where the client application can/must use a simple DB technology while the WEB server must (or at least should) uses a more advanced client-server solution.