Adobe coldfusion tutorials beginners

It is called "T-SQL". You will need to learn SQL since, as mentioned before, a large part of the purpose for existence of any web development language is ability to interact with a database. Interaction means getting data from the database, changing data, inserting data and removing data.

I will now provide few more examples of SQL statements. Once you get data from the database you treat returned data as you would any other query. I suggest you learn all you can about SQL, as it will become the most important after ColdFusion language you are going to use in your career as a web developer.

I am sure you are already familiar with web forms. They are everywhere and are associated with dynamic web. Forms themselves are usually written in pure HTML, however, they frequently need a lot of processing after they are submitted i. You need to verify user input on server side using only client side validation in the form of JavaScript is bad practice and shows how little some people know about proper web development techniques and possibly interact with the database.

In this section I will show you how to build a sample form and the "form target" page. Forms are created in HTML using special set of form building tags.

Lets build a simple form and then a simple target page. This is how the above form looks like when displayed to the end-user: Enter some text here Check if you like this guide Check if you don't. Now, I will create the target page, the one referred to as the "targetPage.

Note that I am going to use "post" method to send my form information to the target page. Post operation will create "form" scope variables on my target page. Almost in every case you want to use method "post" since it allows for much more data to be sent to the target page.

However, "url" method is the default for historical reasons. The "url" method will create "url" scoped variables, not "form" scoped. For more information about "form" and "url" scoped variables, please refer to one of the previous sections of this tutorial. As you can see, we use "form" scoped variables on the target page as we would any other variables. Now, a quick introduction to a cousin of the "form" scope - "url" scope.

The variables in the "url" scope are created by ColdFusion on the page in which query string we have some defined values. The first variable will have the value of "tom", the second will have the value of "programmer".

The "url" variables are a quick way to transfer variables and their values from page to page. Please note that for both "url" and "form" scopes you don't need to specify "form" or "url" strings in front of variables that are in the "url" and "form" scopes.

ColdFusion will search all scopes that don't need to be explicitly specified by the user for your variables and their values. For flexibility reasons for example, you want to be able to accept both "form" scope variables as well as "url" scoped variables you may omit "url.

However, for most applications it is a good practice to specify which scope you are in for clarity. Also, ColdFusion first searches the "variables" scope, then other scopes - thus the process of searching for "form" and "url" variable values if no scope is explicitly stated takes time. One of the most important concepts in functional programming language group are the concepts of "if statement" and "loop statement". Both of these are very fundamental and their syntax should be one of the first things programmers learn in new language.

The "if statement" is a form of a question. If something is true then do this, if something is not true, do something else if defined, else proceed without doing anything.

Lets look at the following examples:. The first one is placed as the last condition inside the if block - it executes only if all cases above fail.

The second one is used to expand on the first if condition - provide alternative if statements in a long chain - trying to catch specific user input. The most important thing to remember about the if statement is what it evaluates - it checks for truth. For example, as above, it checks whatever it is True that x is equal to 5. If it is true, then what follows is executed, if not, then case is skipped.

I will provide here now a short list of most common comparison elements used. Comparison operators are not case sensitive when comparing strings. You may also use logic operators in ColdFusion when evaluating truth value, you may use "and", "or" and "not". Now its time for introduction of the "loop statement". We start with a simple counter loop, where we count from 1 to The purpose of loops is to repeat certain action for specific number of times.

There are few other flavours of loop: conditional - loop execute till some condition specified stays true. You can use cfoutput to print out query sequentially, but cfoutput is limited, it cannot be nested unless you use group by. List is a string that is delimited divided by certain character. Most common character used is a comma. For example, the following is a list of three elements delimited by a comma: "1,2,3".

Collection - loops over elements in a structure. They are used to simplify web development and in re-use of code. There are two types of functions, functions that are written by you and functions that are defined in ColdFusion build in functions. One of the most useful functions is isDefined. It is used to check whatever a variable is defined. It returns true, if it is, false otherwise. There are many more functions build into ColdFusion.

For a complete list of build in functions, take a look at the manual to find out about other functions. Good knowledge of functions is essential to you success as a web developer, together with knowledge of almost all build in tags. Note that we already used some functions in previous examples, without stating that we are using functions. After a short example illustrating the use of build in functions, I will explain how to create your own functions. I will now explain how to create functions using tags you can also create functions in ColdFusion script.

What is inside this tag definition is part of function body and will be executed when the function is called. Functions in ColdFusion can return only one value i. If you need to return multiple values - just build them into a single structure.

Your functions don't need to return a vlaue - it is said that their return value is of type "void". Your functions may also produce output to the screen - they can be used as display functions. Lets look at few examples of function definition with explanation as to what each part of the definition and body does. In above function declaration, we see that all of function body is surrounded by cffunction tags. However, it is a good idea to include more information than the bare minimum about your new function.

This extra information will help you or someone using your code later on. This tag is used to specify information about the values that you are going to accept into your function from the outside place where your function is used. For more information about this tag I am going to send you to ColdFusion manual. Inside above function you see that I have used "var" before the name of the variable. This means that these variables will only be accessed from within this particular function's body.

They are private to this function. It is a good programming practice to define variables only in scopes they are going to be used - there is no point of making every variable global. You will understand why it is so important when you write your first large program and realize that usage of variables in the most global scopes like session or application is only good for variables that actually need to be accessible from so many places in your application.

Just think of what a mess it would be if you had hundreds of variables accessible from everywhere in your application. How would you ever keep track of all of them? If you are returning something from your function then you need to use this tag. However, if you are not returning anything from your function than you cannot use this tag i. There are other ways of calling functions, but they are less used, for now the above two will suffice.

If you were to call additionSample function from the previous example, you would need to add two parameters both numeric. Think about components as objects - they are ColdFusion answer to the basic requirements of object oriented design. The whole discussion of object oriented programming is well beyond the scope of this tutorial.

All I will do here is tell you how to create and access CFCs. CFCs were introduced in version 6 of ColdFusion. They are stored in files with extension of ". For example, component names car will be stored in file named "car. You only store one component per file. Inside CFC you have multiple function definition. Some functions are "public" - for use outside the component, some are for use in the component only - they are "private". All functions contained in a CFC should have a similar purpose.

For example, they are responsible for database access. The following is an example of CFC definition with some functions in it. You will notice that we have used another scope above, "this". This special scope refers to the "properties" that exist inside components.

These properties can be set from outside of a component - they are not private. On the other hand, variables defined without the use of "this" scope are private to the component they were defined in. Now I will show you how you use your new component inside your ColdFusion template you may also initiate components inside other components. The "name" parameter of this tag is a variable you are going to use to access all methods functions that are members of objects are called methods contained within your CFC.

The variable you use stores component definition. You may think of it as a special scope used only for that particular component. For more information about components, once again, you need to look into CF manual and also here. There is another method of initialization of not whole CFCs but of methods in them. Once method is invoked CFC is created just for the time needed for method invocation to complete.

For more information, please take a look at the help files. Here I present a list of useful things you should know about ColdFusion that don't fit into any of tutorial topics above. The list contains all sorts of things that will make you a advanced CF developer in shortest possible time.

I hope you enjoyed my short introduction to ColdFusion. It is in my opinion the easiest to learn web development language. Through it is easy to learn it can be used for applications that all other web development languages are used for.

If CF is too slow at some task, or unable to do them you can always extend it. ColdFusion is a front end to a more powerful Java language, which comes with all the bells and whistles modern programming languages have to offer. If you found some mistakes in this guide, would like to contribute some of your own work, or have some problems with the examples presented above, feel free to contact the author. You can use contact information contained on my website.

NET 4. Poll How do you rate usefulness of this basic ColdFusion tutorial? All rights reserved. If you use any of the content on this page in your own work, please use the code below to cite this page as the source of the content. Stewart, Suzy. After Hours Programming. Accessed on January 13, Accessed 13 January, You must be logged in to post a comment. This site uses Akismet to reduce spam.

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