This document outlines how relational databases differ from
traditional "flat-file" databases, and illustrates how the power of a
relational database can be put to use. Introduction
If
you're already using databases to keep track of information, create
mailing labels, and the like, you know how handy they can be. But when
the relational capabilities of modern databases are put to use, they become much more powerful and useful. The Value of Relationships
Databases that stand alone (i.e. "flat-file") are helpful,
but what happens when you have several stand-alone databases with
overlapping data? For example, if you have created a volunteer database,
a tutor scheduling database, and a donor database, the same person
may be listed in all three databases. Keeping that person's contact
information up to date means updating each database.
Relational
database design can eliminate this problem. The secret is in how
individual databases can share information with each other in a
relational fashion.
In the example above, you could create a contact database, and
using a join command, the volunteer, tutoring, and donor
databases could each use that contact information. You'd only have
to update the contact database once, and all content information
accessed by the other databases would automatically update.
This also helps in database design, because you can create small, independent databases, and link them up later at some point. Relational Database Tools
Relational databases used to be the exclusive domain of high-cost,
high-powered computers used in corporations and government agencies.
Forunately their power is now integrated into commonly-used database
applications such as Microsoft Access and FileMaker Pro.
If
you already have one of these applications and have been using it to
build databases for your Senior Corps project, you may be ready to step
up to relational database design. Key Concepts
Normalizing data
is the process of ensuring that when you build separate databases that
will work together, you do not duplicate information. To use the
contact database as an example, you want to be sure that there is no
contact information in the tutor scheduling or donor databases, because
if the same data (such as a contact's phone number) is in two different
databases, it negates the value of using relational database techniques
in the first place.
Creating key fields makes the sharing of information between
databases possible. For example, by creating a key field called
"ContactID," any reference to the contact with a specific ContactID
will allow you to access information about that person from all
three linked databases.
The key fields are generally created in a join file, which is an in-between file that allows separate databases to access information that links them together.
Relational
database development takes some time to learn, and there are more
concepts involved, but the best way to get started is to take a look at
the resources suggested on this website. |
