Form & Database design basics
What is Database?
We can say it’s a collection of data. Database contains tables. If you ever
heard about Microsoft excel, you can understand database easier. These days,
lots of sites that we visit on web are using database.(Google, Ebay etc.)
There are two types of database , which are called “Flat-File” and “Relational”
databases. Flat-File style of database is for small amounts of data. They made up
of set of strings in one or more files. Therefore it’s great for storing simple lists
but , it can be complicated when you try to replicate more complex data’s.
However , it doesn’t mean that its impossible to store complex data in flat-file
database , it would be more expensive or waste of time. Relational databases are
storing in the tables. You can store lots of data’s in it. It won’t be too
complicated because of the tables. When we talk about the database , we mean
relational database.
What is Database Design?
It’s the process of producing a detailed data model of a database.
We can think database design is like flowcharts. Therefore we can it helps us to
reach the data easily and understand the database. It’s the process of producing a
detailed data model of a database.
Database Design Process
Whatever you choose for topic , every database should perform certain
analysis and design activities. We can separate database design process in to 5
main headers. First one is ; Defining the System Parameters. Ideally , every
project should begin with a clear definition , you have to know what you are
trying to do? and why you are doing it? Once you understand what you are
doing and why you are doing it , you can start to ask yourself “how are you
going to do it?”. Secondly , Defining the Work Processes. The majority of
database systems support one or more work process. The users are not just
storing the data’s for sake , they are storing it , because someone will use them
one day. Thirdly , Building the Conceptual Data Model. More than simply a set
of table structures , the data model defines the data usage for the entire system.
Fourthly , Preparing the Database Schema. It translates the data model into
images. It includes a description of the tables that will be implemented in the
system. Finally , Designing the User Interface .No matter how impressive the
technical performance of your system , if the user interface is confusing or
useless the project will have a big chance to be unsuccessful.
Tables
Think of it’s as being like a rectangular spreadsheet made up of rows and
columns. Each column specifies the type of data stored such as numbers or
strings. We can also think like in c or c++, array of structs.
Query
A database query is a request for information from a database such as
“What course are u taking?” All queries are intended to return o list of devices.
What is a database form?
A database form can be used to facilitate database data entry and retrieval
operations. A database developer usually designs a form which can then be used
by personal without any specific database skills to perform repetitive tasks.
Primary Key
The primary key of a relational table uniquely identifies each record in the
table. For example someone might create codes such as TLC for the Laser
Club and JS for Jone Services. At first, this my seem like a good idea the
codes are short and by looking at them you can figure out which distributes
they reference .But what happens if one of the companies changes its name?
For this reason Avoiding meaningful primary key.
Normalization
Normalization is a process of organizing the data in database in more
efficient way. It is main goal is designing relational tables to minimize
repeating tables and information. This process protects the database against
structural problem.
First Normal Form
Eliminate repeating groups. In my example there are people who knows
different database programs, some of them might know more than one. If we ask
a question “who knows access” we have to scan the whole list for references to
access. This is in efficient, so moving the know databases into a separate table
can solve our problem. Separating the repeating groups of databases from the
member information results in first normal form.
Second Normal Form
Eliminate redundant data. In my database table primary key is member ID
and database ID but the same database name appear redundantly every time its
ID appears in the database table. For example if you want to reclassify a
database or give it databases ID then you have to change it for every member
that is listed in that database. To avoid this problem we have to separate the
attributes depending on database ID. So we create two tables. Database table
which gives name for each database and member database which lists the
database for each member. This is called eliminate redundant data.
Third Normal Form
Eliminate columns not dependent on key .When we need to add more
information in our database such as company name or company location it might
cause a problem, because our key is member ID but the company name and
company location describes only a company not a member so to achieve third
normal form we have to move this data to anew table. When we create company
table then company code becomes the key of new company table .This
separation makes our database more efficient because when we want to change a
company location or something like this. We only need to change the location
column in company table. Otherwise we had to change whole company location
data in member table.
What Can a Form Designer Do?
Get the point : You may be asking for too much information. Users are
reluctant to volunteer information, especially if what you're asking for seems
irrelevant.
Add help information : Help the user with tool tip text.
Provide a clear confirmation message :You should clearly confirm that
the form has been received - send them to a receipt message display on a Web
pages.
Warning Message : In order to use warning message with msgbox or
another page , we use clear information down to the textbox, label , checkbox
ext, or we use a link for guide the user.
Can MENTEŞ Ahmet Korhan ZIVRALI