Welcome!

You will be redirected in 30 seconds or close now.

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

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
WebRTC adoption has generated a wave of creative uses of communications and collaboration through websites, sales apps, customer care and business applications. As WebRTC has become more mainstream it has evolved to use cases beyond the original peer-to-peer case, which has led to a repeating requirement for interoperability with existing infrastructures. In his session at @ThingsExpo, Graham Holt, Executive Vice President of Daitan Group, will cover implementation examples that have enabled ea...
SYS-CON Events announced today that Numerex Corp, a leading provider of managed enterprise solutions enabling the Internet of Things (IoT), will exhibit at the 19th International Cloud Expo | @ThingsExpo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Numerex Corp. (NASDAQ:NMRX) is a leading provider of managed enterprise solutions enabling the Internet of Things (IoT). The Company's solutions produce new revenue streams or create operating...
Fifty billion connected devices and still no winning protocols standards. HTTP, WebSockets, MQTT, and CoAP seem to be leading in the IoT protocol race at the moment but many more protocols are getting introduced on a regular basis. Each protocol has its pros and cons depending on the nature of the communications. Does there really need to be only one protocol to rule them all? Of course not. In his session at @ThingsExpo, Chris Matthieu, co-founder and CTO of Octoblu, walk you through how Oct...
As ridesharing competitors and enhanced services increase, notable changes are occurring in the transportation model. Despite the cost-effective means and flexibility of ridesharing, both drivers and users will need to be aware of the connected environment and how it will impact the ridesharing experience. In his session at @ThingsExpo, Timothy Evavold, Executive Director Automotive at Covisint, will discuss key challenges and solutions to powering a ride sharing and/or multimodal model in the a...
"My role is working with customers, helping them go through this digital transformation. I spend a lot of time talking to banks, big industries, manufacturers working through how they are integrating and transforming their IT platforms and moving them forward," explained William Morrish, General Manager Product Sales at Interoute, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
According to Forrester Research, every business will become either a digital predator or digital prey by 2020. To avoid demise, organizations must rapidly create new sources of value in their end-to-end customer experiences. True digital predators also must break down information and process silos and extend digital transformation initiatives to empower employees with the digital resources needed to win, serve, and retain customers.
If you’re responsible for an application that depends on the data or functionality of various IoT endpoints – either sensors or devices – your brand reputation depends on the security, reliability, and compliance of its many integrated parts. If your application fails to deliver the expected business results, your customers and partners won't care if that failure stems from the code you developed or from a component that you integrated. What can you do to ensure that the endpoints work as expect...
In this strange new world where more and more power is drawn from business technology, companies are effectively straddling two paths on the road to innovation and transformation into digital enterprises. The first path is the heritage trail – with “legacy” technology forming the background. Here, extant technologies are transformed by core IT teams to provide more API-driven approaches. Legacy systems can restrict companies that are transitioning into digital enterprises. To truly become a lea...
IoT is fundamentally transforming the auto industry, turning the vehicle into a hub for connected services, including safety, infotainment and usage-based insurance. Auto manufacturers – and businesses across all verticals – have built an entire ecosystem around the Connected Car, creating new customer touch points and revenue streams. In his session at @ThingsExpo, Macario Namie, Head of IoT Strategy at Cisco Jasper, will share real-world examples of how IoT transforms the car from a static p...
Cloud computing is being adopted in one form or another by 94% of enterprises today. Tens of billions of new devices are being connected to The Internet of Things. And Big Data is driving this bus. An exponential increase is expected in the amount of information being processed, managed, analyzed, and acted upon by enterprise IT. This amazing is not part of some distant future - it is happening today. One report shows a 650% increase in enterprise data by 2020. Other estimates are even higher....
From wearable activity trackers to fantasy e-sports, data and technology are transforming the way athletes train for the game and fans engage with their teams. In his session at @ThingsExpo, will present key data findings from leading sports organizations San Francisco 49ers, Orlando Magic NBA team. By utilizing data analytics these sports orgs have recognized new revenue streams, doubled its fan base and streamlined costs at its stadiums. John Paul is the CEO and Founder of VenueNext. Prior ...
One of biggest questions about Big Data is “How do we harness all that information for business use quickly and effectively?” Geographic Information Systems (GIS) or spatial technology is about more than making maps, but adding critical context and meaning to data of all types, coming from all different channels – even sensors. In his session at @ThingsExpo, William (Bill) Meehan, director of utility solutions for Esri, will take a closer look at the current state of spatial technology and ar...
The Internet of Things can drive efficiency for airlines and airports. In their session at @ThingsExpo, Shyam Varan Nath, Principal Architect with GE, and Sudip Majumder, senior director of development at Oracle, will discuss the technical details of the connected airline baggage and related social media solutions. These IoT applications will enhance travelers' journey experience and drive efficiency for the airlines and the airports. The session will include a working demo and a technical d...
What happens when the different parts of a vehicle become smarter than the vehicle itself? As we move toward the era of smart everything, hundreds of entities in a vehicle that communicate with each other, the vehicle and external systems create a need for identity orchestration so that all entities work as a conglomerate. Much like an orchestra without a conductor, without the ability to secure, control, and connect the link between a vehicle’s head unit, devices, and systems and to manage the ...
Businesses are struggling to manage the information flow and interactions between all of these new devices and things jumping on their network, and the apps and IT systems they control. The data businesses gather is only helpful if they can do something with it. In his session at @ThingsExpo, Chris Witeck, Principal Technology Strategist at Citrix, will discuss how different the impact of IoT will be for large businesses, expanding how IoT will allow large organizations to make their legacy ap...
The many IoT deployments around the world are busy integrating smart devices and sensors into their enterprise IT infrastructures. Yet all of this technology – and there are an amazing number of choices – is of no use without the software to gather, communicate, and analyze the new data flows. Without software, there is no IT. In this power panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, panelists will look at the protocols that communicate data and the emerging data analy...
SYS-CON Events announced today that Commvault, a global leader in enterprise data protection and information management, has been named “Bronze Sponsor” of SYS-CON's 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Commvault is a leading provider of data protection and information management solutions, helping companies worldwide activate their data to drive more value and business insight and to transform moder...
What are the new priorities for the connected business? First: businesses need to think differently about the types of connections they will need to make – these span well beyond the traditional app to app into more modern forms of integration including SaaS integrations, mobile integrations, APIs, device integration and Big Data integration. It’s important these are unified together vs. doing them all piecemeal. Second, these types of connections need to be simple to design, adapt and configure...
Digital innovation is the next big wave of business transformation based on digital technologies of which IoT and Big Data are key components, For example: Business boundary innovation is a challenge to excavate third-party business value using IoT and BigData, like Nest Business structure innovation may propose re-building business structure from scratch, as Uber does in the taxicab industry The social model innovation is also a big challenge to the new social architecture with the design fr...
A strange thing is happening along the way to the Internet of Things, namely far too many devices to work with and manage. It has become clear that we'll need much higher efficiency user experiences that can allow us to more easily and scalably work with the thousands of devices that will soon be in each of our lives. Enter the conversational interface revolution, combining bots we can literally talk with, gesture to, and even direct with our thoughts, with embedded artificial intelligence, wh...