Database Manager Tutorial - Introduction
A database is a collection of information (data) organized to make it
easy to manage, and perform searches on. The best way to explain what databases are and how they can be used,
is best detailed using an example.
Say we wanted to collect information on family members. The information
we could have the software collect (remember, this is just an example) is :
First Name, Last Name, Street Address, City, State, ZIP code and Age
Each set of information for a family member would be called a database 'record'.
Each piece of information (First Name, City...) within a record is called
a database 'field'. So this database would have seven fields per record.
There are many different database field types, as they contain different kinds of information.
The types of fields/information supported this online database management software are :
- Text : plain text, such as first name, street address and so on
Once we collected our information, things get interesting. This web based software will allow you to
either 'list' or 'search' records (family members) in the database.
- Numeric : information that can be expressed as a number, say age in our
example. While we could define the ZIP code as a number, 'Numeric' field types
are usually reserved for numbers we want to compare to other numbers. Age would
make sense here as we could then ask the database manager to tell us who is older than 50
- Date : this field type holds dates, such as birth dates. Age would not be a
date field as is is not the same as the date a family member was born on. These
field types take the format of month/day/year. The month is two digits (01-12), the day
is two digits long also (01-31) and the year is four digits long (2000 for example).
- Time : this field type holds times, such as the time a family member has their
alarm clock set for. This field type is expressed in military time. The format is hour:minute.
The hour value is two digits long (00 - 24) and the minute value is also two digits
long (00 - 59).
- Boolean : this field type holds a 'yes' or 'no' value. It could be used
to hold information such as the family members gender. Male could equal 'Y' (for 'yes') and
female could equal 'N' (for 'no'). If we wanted to organize an evening for the men or women in the family, you could then ask the database software to list family members of only the gender you wish to invite.
- Password : this is an encrypted password. It could be used to make it so that
family members can only view their own information in the database.
- Index : if you have two family members with the same name you could not locate the
correct person by feeding the online database software their name. In such cases, you could add an 'index'
field to your database. This is basically a numeric value, we'll call uncle frank '1' and cousin frank '2',
just so we can keep them apart.
The 'list' option/command would simply show us the records in our database. Say we wanted to write
all of them a letter, we could have the database show us the addresses for every family member.
The 'search' option/command makes things more interesting. Say you plan to go to a comedy club
where alcohol is served (making it so that family members under 21 could not join you, in the US anyway), you could
ask the database to only list family members with an age greater than 20 (listing family members over 21 only).
As you can see by now this has some potential to manage information on our family members.
Now, apply the same potential to an online database of products, resumes, real estate listings or any other set of information.
This is where it gets interesting and this software can be used to make it easier for people
who visit your web site to find the information they want quickly.