Welcome!

ColdFusion Authors: Yakov Fain, Maureen O'Gara, Nancy Y. Nee, Tad Anderson, Daniel Kaar

Related Topics: ColdFusion

ColdFusion: Article

The Relational Database: Center of Most Advanced Applications

Don't let proper database design remain a mystery to you

You won't get very far while building ColdFusion applications without the need for a relational database. Since ColdFusion is so easy to use, many developers come from non-programming based backgrounds, and proper database design remains a mystery.

Perhaps you've worked on other applications, such as a spreadsheet application in Microsoft Excel or used an Access database with a single table to store data. Both of these options serve their purpose, however they are not the best choice for web applications. In this architecture focus issue, I wanted to take some time to introduce you to relational database concepts.

Understanding the Terms
Before I start blabbing about database this and database that, I want to make sure you understand what I'm saying. So let's start by defining some common terms that you should be familiar with.

  • Database: A database is any collection of related data. It could be as simple as a grocery list or as complex as a full Enterprise Resource Planning application. The database is made up of many elements, starting with...
  • Tables: A table is similar to a single spreadsheet. A relational database is made of multiple tables. Tables are made up of columns and rows. A column represents a single piece of data, such as a name, zip code, or street address. A row represents a single set of all columns. No two rows within a table can be identical. You can relate tables together using ...
  • Keys: There are two types of keys in a relational database. A primary key is a column, or group of columns, that can uniquely identify a single row in the table. A foreign key is a column in one table that can be used to uniquely identify the row from another table. It is through the use of primary and foreign keys that you define relations between tables.
The act of designing a database is to take your data, and define the tables and relationships that you want to store it. This process is often called database normalization.

Database Normalization
Normal forms are a way to check that your database structure is correct. There are seven different levels of normal forms and each normal form exists to avoid a certain anomalies, that will not allow you to insert, or delete, data without also inserting or deleting a piece of unrelated data. You probably don't need to know specifics about the each level of normal forms. When developing a database, you just want to think about storing each piece of data only one time. You don't want duplicates. In your table structure, have you duplicated data somewhere? If so, you may want to re-work your structure so that you don't.

This will probably make more sense with an example. Suppose you were writing a program to catalog your CDs. You might start with a list of sample data, maybe something like Table 1. This is a table with four columns: Artist, Album Name, Genre, and AlbumID. The AlbumID is intended to be the primary key of this table. In a real application, you'll probably have a lot more data, such as a song list for each album, release dates, or the names of band members. We'll keep it simple for this example, though. If you examine the data, you'll notice some places where the data is duplicated. The artist name, Guster appears twice. The genres Grunge, and Alternative appear twice. If you were building an on-line record store, you would not want to store the genre or artist name a lot of times.

This table also exhibits insertion and deletion anomalies, which were discussed earlier. What happens if you want to delete the Bishop Allen album? You will also inadvertently delete the "Rock" genre. That is a deletion anomaly. What if you wanted to create a genre for blues? You wouldn't be able to do so without also entering an album. That is an insertion anomaly. You want to build your tables to avoid these sorts of issues. So, how do you do it?

Well, in this situation, you may first want to separate the Genre into its own table. You can see the genre table in Table 2. I added a GenreID column to the table. This is an integer column intended to be the primary key of the table. We can also split out the artist information into a separate table, as shown in Table 3. The table has two columns, a primary key named ArtistID and an artist column. With the artist and genre information moved into their own tables, what does your original album table look like? There isn't much left, just a primary key and an album name. However, you'll still want to preserve the relationships between the album, genre, and artist tables. How do you do this? You take the primary key of the genre and artist tables and put then in the album table. Our updated album table is shown in Table 4.

Why is this different? Well, it takes less disk space to store an integer than it does text. While you probably won't notice any problems in tables with just a few rows, the difference becomes much greater when you are dealing with larger amounts of data, such as a song database with a thousand records, such as iTunes. Each little bit starts to add up.

Database Relationships
There are really three different types of relationships that come into play when putting your data into tables. The first type is called a one-to-one relationship. This means that for any single piece of data A, there will only be a single piece of data B. If A, were a username, then B might be a password. For every username, there must be only one password and for every password there must be only one username. In most one to one relationships the data is stored in the same table. If for some reason you are splitting the data between two tables, you can represent the relationship by moving the primary key from either table into the other table as a foreign key.

The next type of relationship is a one-to-many relationship. This means for every piece of data A, there will be multiple pieces of data B. For every piece of data B, there will only be one piece of a data A. A good example of this is the artist/album, which we described above. For every artist, there may be multiple albums. But, each album only has a single artist. (For the sake of this example we are ignoring multi band compilations). You can represent one-to-many relationships by taking the primary key of the "one" side and put it into the table of the "many" side as a foreign key. This is what we did to split up the album and artist tables. Our example, above, created the genres and albums relationship as one-to-many.

The third type of relationship is a many-to-many relationship. This means that for every piece of A data there will be multiple pieces of B data, and for every piece of B data there will be multiple pieces of A data. Perhaps, you've got the Aerosmith album. It's rock. It's blues. Where do you categorize it? The Genre relationship to an album could be a many-to-many relationship. To implement this type of relationship in the database, we create a special type of table, often called an intersection or linking table. This table does not usually contain any data, only the primary keys of the two tables that it is linking. To implement a many-to-many relationship between genres and albums, we would use the GenreID from the albums table and create a new table, as shown in Table 5.

I know it looks like a table of numbers, and that's what it is. The primary key of intersection tables is usually made up of all the columns in it.

Common Database Design Mistakes
Before wrapping up this column, I want to finish off by pointing out some mistakes I often see beginner developers making. All of these are obvious in hindsight, but you probably don't realize you did it "wrong" until you have a problem and the light bulb inside in your head brightens up, and "Uh-oh" escape from your lips.

  • Names: You have a site registration, or an address book application, or something that requires you to collect and store the names of your users. Make sure that you store the first name and last name as separate columns in a database table, do not combine them. If the data is being collected, at some point you are going to be asked to do a mail merge. When you do that, it'll be a lot easier to do if you have the first and last names separate, so you can address people as "Mr Houser" instead of "Mr Jeff Houser."
  • Deleting Data: It's easy to write a delete statement in SQL, but what happens when your client or boss calls up to ask where their data went? If the data is truly deleted, you have no way to restore it. If you're lucky you have backup tapes, from which you can restore yesterday's data, but that can get messy. A better way is to not ever allow users to directly delete data. Create a Boolean field in your database table called Deleted. If set to 1, the record is flagged for deletion. If set to zero, the record is fine. You can run batch scripts on a routine basis to delete the data, as needed. When the user calls up to find out where their data is located, you can just flip that flag to restore it for them.
  • Store the Date: At some point, someone is going to want to look at the data you've been collecting through the web site. When are people registering on the site? When was the last time they modified their information? On most tables, I will add a "DateCreated" field to store the time that the record in the database was created, and a "DateLastModified" field to store the time the data was last modified. On some projects, I've had a few "higher ups" quite shocked that this data was not being collected.
  • Define Relationships: You should always make sure you use the built-in facilities of your database to specify keys, and define relationships between tables. In addition to helping you protect your data from inadvertent corruption, the database engine can often use these relationships and keys to automatically optimize queries. I've had quite a few sleepless nights trying to fix the invalid data that had resulted from deleting one piece of data, without deleting data that relates to it. For example, what if we deleted a genre, but did not delete the entries in our intersection table that related to that genre? Something is going to break somewhere.
Those were just some of the more common mistakes I've made myself or seen others make.

What Next?
The relational database is the center of most advanced applications, web-based or otherwise. Some of the more common databases used in ColdFusion development are SQL Server, MySQL, and PostgreSQL. Oracle often shows up on sites with larger load, and Access will sometimes show up on smaller sites. I would recommend putting aside some time to learn about the database of your choice, because many of the skills you learn can easily be transferred to all database platforms.

More Stories By Jeffry Houser

Jeffry is a technical entrepreneur with over 10 years of making the web work for you. Lately Jeffry has been cooped up in his cave building the first in a line of easy to use interface components for Flex Developers at www.flextras.com . He has a Computer Science degree from the days before business met the Internet and owns DotComIt, an Adobe Solutions Partner specializing in Rich Internet Applications. Jeffry is an Adobe Community Expert and produces The Flex Show, a podcast that includes expert interviews and screencast tutorials. Jeffry is also co-manager of the Hartford CT Adobe User Group, author of three ColdFusion books and over 30 articles, and has spoken at various events all over the US. In his spare time he is a musician, old school adventure game aficionado, and recording engineer. He also owns a Wii. You can read his blog at www.jeffryhouser.com, check out his podcast at www.theflexshow.com or check out his company at www.dot-com-it.com.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


@ThingsExpo Stories
SYS-CON Events announced today that SOA Software, an API management leader, will exhibit at SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. SOA Software is a leading provider of API Management and SOA Governance products that equip business to deliver APIs and SOA together to drive their company to meet its business strategy quickly and effectively. SOA Software’s technology helps businesses to accelerate their digital channels with APIs, drive partner adoption, monetize their assets, and achieve a...
From a software development perspective IoT is about programming "things," about connecting them with each other or integrating them with existing applications. In his session at @ThingsExpo, Yakov Fain, co-founder of Farata Systems and SuranceBay, will show you how small IoT-enabled devices from multiple manufacturers can be integrated into the workflow of an enterprise application. This is a practical demo of building a framework and components in HTML/Java/Mobile technologies to serve as a platform that can integrate new devices as they become available on the market.
BSQUARE is a global leader of embedded software solutions. We enable smart connected systems at the device level and beyond that millions use every day and provide actionable data solutions for the growing Internet of Things (IoT) market. We empower our world-class customers with our products, services and solutions to achieve innovation and success. For more information, visit www.bsquare.com.
Almost everyone sees the potential of Internet of Things but how can businesses truly unlock that potential. The key will be in the ability to discover business insight in the midst of an ocean of Big Data generated from billions of embedded devices via Systems of Discover. Businesses will also need to ensure that they can sustain that insight by leveraging the cloud for global reach, scale and elasticity.
SYS-CON Events announced today that Red Hat, the world's leading provider of open source solutions, will exhibit at Internet of @ThingsExpo, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Red Hat is the world's leading provider of open source software solutions, using a community-powered approach to reliable and high-performing cloud, Linux, middleware, storage and virtualization technologies. Red Hat also offers award-winning support, training, and consulting services. As the connective hub in a global network of enterprises, partners, a...
SYS-CON Events announced today that Utimaco will exhibit at SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Utimaco is a leading manufacturer of hardware based security solutions that provide the root of trust to keep cryptographic keys safe, secure critical digital infrastructures and protect high value data assets. Only Utimaco delivers a general-purpose hardware security module (HSM) as a customizable platform to easily integrate into existing software solutions, embed business logic and build s...
How do APIs and IoT relate? The answer is not as simple as merely adding an API on top of a dumb device, but rather about understanding the architectural patterns for implementing an IoT fabric. There are typically two or three trends: Exposing the device to a management framework Exposing that management framework to a business centric logic • Exposing that business layer and data to end users. This last trend is the IoT stack, which involves a new shift in the separation of what stuff happens, where data lives and where the interface lies. For instance, it’s a mix of architectural style...
Connected devices are changing the way we go about our everyday life, from wearables to driverless cars, to smart grids and entire industries revolutionizing business opportunities through smart objects, capable of two-way communication. But what happens when objects are given an IP-address, and we rely on that connection, sometimes with our lives? How do we secure those vast data infrastructures and safe-keep the privacy of sensitive information? This session will outline how each and every connected device can uphold a core root of trust via a unique cryptographic signature – a “bir...
SYS-CON Events announced today that Matrix.org has been named “Silver Sponsor” of Internet of @ThingsExpo, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Matrix is an ambitious new open standard for open, distributed, real-time communication over IP. It defines a new approach for interoperable Instant Messaging and VoIP based on pragmatic HTTP APIs and WebRTC, and provides open source reference implementations to showcase and bootstrap the new standard. Our focus is on simplicity, security, and supporting the fullest feature set.
Internet of @ThingsExpo Silicon Valley announced on Thursday its first 12 all-star speakers and sessions for its upcoming event, which will take place November 4-6, 2014, at the Santa Clara Convention Center in California. @ThingsExpo, the first and largest IoT event in the world, debuted at the Javits Center in New York City in June 10-12, 2014 with over 6,000 delegates attending the conference. Among the first 12 announced world class speakers, IBM will present two highly popular IoT sessions, which will take place November 4-6, 2014 at the Santa Clara Convention Center in Santa Clara, Calif...
P2P RTC will impact the landscape of communications, shifting from traditional telephony style communications models to OTT (Over-The-Top) cloud assisted & PaaS (Platform as a Service) communication services. The P2P shift will impact many areas of our lives, from mobile communication, human interactive web services, RTC and telephony infrastructure, user federation, security and privacy implications, business costs, and scalability. In his session at Internet of @ThingsExpo, Robin Raymond, Chief Architect at Hookflash Inc., will walk through the shifting landscape of traditional telephone a...
WebRTC defines no default signaling protocol, causing fragmentation between WebRTC silos. SIP and XMPP provide possibilities, but come with considerable complexity and are not designed for use in a web environment. In his session at Internet of @ThingsExpo, Matthew Hodgson, technical co-founder of the Matrix.org, will discuss how Matrix is a new non-profit Open Source Project that defines both a new HTTP-based standard for VoIP & IM signaling and provides reference implementations.

SUNNYVALE, Calif., Oct. 20, 2014 /PRNewswire/ -- Spansion Inc. (NYSE: CODE), a global leader in embedded systems, today added 96 new products to the Spansion® FM4 Family of flexible microcontrollers (MCUs). Based on the ARM® Cortex®-M4F core, the new MCUs boast a 200 MHz operating frequency and support a diverse set of on-chip peripherals for enhanced human machine interfaces (HMIs) and machine-to-machine (M2M) communications. The rich set of periphera...

SYS-CON Events announced today that Aria Systems, the recurring revenue expert, has been named "Bronze Sponsor" of SYS-CON's 15th International Cloud Expo®, which will take place on November 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Aria Systems helps leading businesses connect their customers with the products and services they love. Industry leaders like Pitney Bowes, Experian, AAA NCNU, VMware, HootSuite and many others choose Aria to power their recurring revenue business and deliver exceptional experiences to their customers.
The Internet of Things (IoT) is going to require a new way of thinking and of developing software for speed, security and innovation. This requires IT leaders to balance business as usual while anticipating for the next market and technology trends. Cloud provides the right IT asset portfolio to help today’s IT leaders manage the old and prepare for the new. Today the cloud conversation is evolving from private and public to hybrid. This session will provide use cases and insights to reinforce the value of the network in helping organizations to maximize their company’s cloud experience.
The Internet of Things (IoT) is making everything it touches smarter – smart devices, smart cars and smart cities. And lucky us, we’re just beginning to reap the benefits as we work toward a networked society. However, this technology-driven innovation is impacting more than just individuals. The IoT has an environmental impact as well, which brings us to the theme of this month’s #IoTuesday Twitter chat. The ability to remove inefficiencies through connected objects is driving change throughout every sector, including waste management. BigBelly Solar, located just outside of Boston, is trans...
SYS-CON Events announced today that Matrix.org has been named “Silver Sponsor” of Internet of @ThingsExpo, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Matrix is an ambitious new open standard for open, distributed, real-time communication over IP. It defines a new approach for interoperable Instant Messaging and VoIP based on pragmatic HTTP APIs and WebRTC, and provides open source reference implementations to showcase and bootstrap the new standard. Our focus is on simplicity, security, and supporting the fullest feature set.
Predicted by Gartner to add $1.9 trillion to the global economy by 2020, the Internet of Everything (IoE) is based on the idea that devices, systems and services will connect in simple, transparent ways, enabling seamless interactions among devices across brands and sectors. As this vision unfolds, it is clear that no single company can accomplish the level of interoperability required to support the horizontal aspects of the IoE. The AllSeen Alliance, announced in December 2013, was formed with the goal to advance IoE adoption and innovation in the connected home, healthcare, education, aut...
SYS-CON Events announced today that Red Hat, the world's leading provider of open source solutions, will exhibit at Internet of @ThingsExpo, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Red Hat is the world's leading provider of open source software solutions, using a community-powered approach to reliable and high-performing cloud, Linux, middleware, storage and virtualization technologies. Red Hat also offers award-winning support, training, and consulting services. As the connective hub in a global network of enterprises, partners, a...
The only place to be June 9-11 is Cloud Expo & @ThingsExpo 2015 East at the Javits Center in New York City. Join us there as delegates from all over the world come to listen to and engage with speakers & sponsors from the leading Cloud Computing, IoT & Big Data companies. Cloud Expo & @ThingsExpo are the leading events covering the booming market of Cloud Computing, IoT & Big Data for the enterprise. Speakers from all over the world will be hand-picked for their ability to explore the economic strategies that utility/cloud computing provides. Whether public, private, or in a hybrid form, clo...