Page 20 - Database-En-V3

Database design

What is good database design?
There are some principles that are followed when designing databases, which are:

1. Principle 1: Redundant data (repeating data) is not recorded because it wastes
space and increases the possibility of errors and inconsistencies.

2. The second principle: Any data can be inferred from another, it should not be
recorded

3. The third principle: No result of mathematical transactions is recorded
4. The fourth principle: The completeness and validity of data is an important

matter and guarantees the validity of the information retrieved or inferred. If
the database contains incorrect data, any reports that use this data or
information from the database will also contain incorrect data and
information. Then the decisions will be wrong.

I. Design process
To ensure good database design, the steps of the design process are as follows:

1. Determine the purpose of the database
The purpose of databases is to know how you expect them to be used and who will
use them. For a small school database, for example, the purpose may be “The
student database saves their grades for the purpose of maintaining student records
until they graduate, monitoring their academic achievement and their progress,
and producing the necessary reports for the school’s educational administration.”

2. Identify and organize the required data
To find and organize the data you need, start with existing data. For example, you
can record or keep student data on paper forms. Gather documents and list each
data type that appears on the form. If you do not have any existing forms, imagine
that you had to design a form to record student data.

What data do you want to put in the form? What packing boxes would you like to
create? Identify and list each of these items. For example, an examination of
student records may show that each record contains the student's name, address,
city, zip code, and telephone number as well. Each of these elements represents as
a possible column in table.

When you prepare your database design, don't worry about getting it done right at
a first time. Brain storming, and then list every item that comes to mind. If someone
else uses the database, ask for their thoughts as well. You can adjust this menu
later.

13 Training unit in the field of technological information - at the Supreme Council of Universities © Intellectual property rights 2024