NULL or Empty in Software Development

skyhawk133 — Tue, 02 Dec 2008 08:41:56 -0700

I'm curious which you prefer and why. NULL or Empty. For those of you who don't know, there is a distinct difference between a NULL (or absence of a value) and an empty value. Databases treat NULL and empty differently, and so do various programming languages. In PHP, checking for "" is not the same as checking for NULL.

So which do you prefer and why?

user authentication system -- theory in PHP

capty99 — Mon, 01 Dec 2008 10:27:29 -0700

Hey, so yeah, I'm just trying to think this through and need your help.

I want a user authentication system just like your everyday sites , dreamincode, whatever.

You log in, you can come back to the computer some other time and your still logged in etc...

So, my question is, how do I do that securely.

I mean yes, I could just embed a user id in a cookie and check that cookie everytime, but then they could just modify the cookie to a different id and be logged in someone else's name.

So.... I'm just wondering how that is done normally.

Suggestions wanted heavy data base frontend in Databases

jens — Mon, 01 Dec 2008 08:48:01 -0700

Inspired by another post here I have the following questions:

What would you suggest as a solution, or how would you reason, under the following circumstanses:
- There is a need to present a DB (data base) on the web (build a front end for the DB on the web).
- The DB is quite complex (30+ tables with several many-to-many relations)
- The DB will be quite large (100.000+ (maybe 1M) records per table)
- There will (hopefully) be a lot of concurrent users (perhaps 1000+)
- There will be far more searches then writes to the DB (maybe 50 times more)
- Speed and ease of use for the end user is essential. (Priority one)

Questions:
What language would you recommend (is interpreted a drawback)?
Any DB that you would NOT recommend? (Yeah, I do relize that Access is not a choise) /smile.gif" style="vertical-align:middle" emoid=":)" border="0" alt="smile.gif" />

This is a very open question, mostly in the spirit of trying to avoid any severe pitfalls.

Regards
/Jens

November 2008 Thumb Drive Winner in Competitions

skyhawk133 — Mon, 01 Dec 2008 08:30:08 -0700

kiwi2 won the November 2008 thumb drive! Congratulations!

http://www.dreamincode.net/forums/showtopic70834.htm was the winning submission.

Remember to keep submitting those snippets and tutorials for your chance to win the 1GB Dream.In.Code Thumb Drive! And be sure to check out the new monthly top contributor giveaway: http://www.dreamincode.net/forums/index.php?showtopic=37074

More Info: http://www.dreamincode.net/forums/showtopic19383.htm

Dream.In.Code Community Awards - Vote! in Dream.in.code News

skyhawk133 — Tue, 25 Nov 2008 21:05:41 -0700

Alright, the nominations are in and it's time to VOTE. This isn't like the presidential election where you could vote early and vote often, you get 1 vote. That's right. 1 vote. Make it count. The voting will end December 15.

Winners will get... something... maybe a badge... maybe a special member title... We'll see how it goes /smile.gif" style="vertical-align:middle" emoid=":)" border="0" alt="smile.gif" />

Votes are anonymous.

Dream.In.Code Rebirth - Now Accepting Feedback in Site Feedback

skyhawk133 — Tue, 25 Nov 2008 17:13:59 -0700

We're growing and in order to better organize the vast amounts of information we have, improve the overall DIC experience, and generally keep DIC an awesome place, we're planning a rebirth of sorts. Since DIC is for you, I want to hear your suggestions.

I've setup a UserVoice account where you can suggest, vote, and comment on ideas specific to the Dream.In.Code Rebirth. We'll try to take every idea in to consideration as we plan and create the new DIC.

Share your ideas: http://dreamincode.uservoice.com

How do you motivate yourself? in Freelancing

skyhawk133 — Sat, 22 Nov 2008 17:20:19 -0700

I've got ADD which certainly doesn't help, but how do you motivate yourself when you just don't feel like working on client projects? I typically crack open a Coke, crank up some music, and try to eliminate outside distractions. But I kind of like having Fox News on in the background while I work.

How do you hold yourself accountable and keep working when you don't want to?

Useful additions to the .Net Framework 3.0 in C# Tutorials

PsychoCoder — Sat, 22 Nov 2008 16:55:50 -0700

Today we're going to be looking at the additions to the .Net Framework with the introduction on version of 3.0. The major additions to the Framework, beginning with 3.0 are items such as:

Now lets take a look at each ot these improvements one at a time:

Lambda Expressions:

Lambda Expressions are, simply put, functions and methods. They can contain expressions and statements, and can be used to create delegates or expressions tree types. Lambda Expressions use the => token. This operator allows us to write anonymous inline functions that look much cleaner. The Lambda Operator is used extensively in LINQ. Not only can make out code much cleaner, and in most cases more efficient. Now lets take a look at how the Lambda Operator:

Without the Lambda Expression
[code=csharp]
class Class1
{
delegate void DoSomethingDelegate();
public void InvokeMethod()
{
DoSomethingDelegate del = new DoSomethingDelegate(SampleMethod);
del();
}

void SampleMethod()
{
Console.WriteLine("Do Something Here");
}
}
[/code]

With the => token (using the Lambda Expression:
[code=csharp]
class Class1
{
delegate void DoSomethingDelegate();
public void InvokeMethod()
{
DoSomethingDelegate del = () => Console.WriteLine("Do Something Here") ;
del();
}
}
[/code]

Notice how much cleaner that code is using the Lambda Expression. It reduced our code from 11 lines to 7 lines total (including the class signature).

Implicitly Typed Variables:

With this new feature a variable can be inferred a data type using the new var keyword. This new keyword are implicitly typed. This keyword is also used extensively in LINQ. Here is an example f how the var keyword works. In 2.0 you declared a variable like this

[code=csharp]
int i = 0;
[/code]

With this new keyword variables can be implicitly typed, like so
[code=csharp]
var i = 0
[/code]

The compiler automatically knows that i is of the int data type.

Anonymous Types:

Anonymouse Types are types (or properties of an object or class) automatically inferred (similar the Implicitly Typed variables) and are created by the object initializers. The object initializer specifies the values from one (or more) properties/fields from an object or class. Simply put you can specify a series or properties from an object or class from a series or assignments, such as

[code=csharp]
{ FirstName = "Richard", LastName = "Smith" }
[/code]

Now your object or class is automatically given these properties. In layman's terms an Anonymous Type is a type that wasn't initially exist and wasn't defined in code. With the example above the compiler creates anonymous typeswith the properties inferred from the objects initializer, meaning the new class will have properties FirstName and LastName.

Remember, if you do not specify names with the anonymous types the compilers will give them members of the same name as the properties used to initialize them. Here's an example of this

[code=csharp]
var query =
from client in Clients
select new { client.FirstName, client.LastName };

foreach (var person in query)
{
Console.WriteLine("FirstName: {0}, LastName: {1}", v.FirstName, v.LastName);
}
[/code]

Notice how the compiler gave FirstName and LastName to the person in the foreach loop.

Expression Trees:

Expression Trees give a way of translating executable code into some form of data. This act can be extremely valuable, especially if you want to modify code that is being executed. It can also be very useful if are wanting to transform or modify some LINQ query into code that operates in a different process, say a database.

They represent language-level code in the form of data, and that data is stored in a tree-shaped format, with each node representing an expression.One of the cool features of the Expression Tree is BuildString on your instance of the Expression Tree, which will retrieve the Lambda Expression of the delegate. Here is an example

[code=csharp]
Expression<Func<int,int,int>> exp = (x,y) => x / y;

//first we invoke our delegate
var original = exp.Compile();
var two = original.Invoke(10,5);

//now we get the Lambda Expression from our expression string
StringBuilder builder = new StringBuilder();
expression.BuildString(builder);
// (x, y) => Divide(x, y)
var lambda = builder.ToString();

// Get Parameters,we have 2 (x, y)
var parameters = exp.Parameters
[/code]

As you can see Express Trees, along with BuildString and the Lambda Expression can greatly improve and simplify our

code.

Extension Methods

Extension Methods are static methods that can be invoked using the instance method syntax. The main difference between Extension Methods and static methods are as follows:

Extension Methods must have the this keyword as the first argument
Extension methods can only be declare within static classes, no so with static methods
The arguments declared in an Extension Method with the this is not passed when the Extension Method is consumed, with a static method no arguments are skipped and all arguments must be entered.
Extension Methods can only be called on instance values
Though Extension Methods are static, there can only be a single instance, otherwise you get a compilation error

Now for an example of a normal Expression Tree, sans the BuildString. Remember Exression Trees are strongly types and they can be assigned from a Lambda Expression and they don't need to be compiled until the moment they are needed.
[code=csharp]
public static void IsRequired<T>(this T obj, Expression<Func<T, bool>> p)
{
var requiredObj = pred.Compile();
if (!requiredObj(obj))
throw new Exception("Object Required: + p.ToString());
}
[/code]

Object & Collection Initialerzs:

This new feature allows programmers to create objects and collections in an expression context rather than a statement context. This is referred to in-line initialization of objects.

Difference between Expression Context and Statement:

Statement Context: Where the compiler expects and car then parse a statement.
Expression Context: First it's much more limited, you can pass an expression to a method, but you're not allowed to write a complete statement where an argument is thus expected

Here is the standard creation of a class
[code=csharp]
public class Person

{

string _name;
int _age;

public Person(string name, int age)
{
_name = name;
_age = age
}

public string Name
{
get { return _name; }
set { _name = value; }
}

public int Age
{
get { return _age; }
set { _age = value; }
}
}
[/code]

You can then initialze the class as such
[code=csharp]
Person person = new Person(name,age);
[/code]

Now with 3.0 not only do you not need to create constructors for your class, you can simply initialze your Person class like so
[code=csharp]
Person person = new Person { Cat.Name = "Richard", Age = 40 };
[/code]

So as you can it's much simpler and uses a lot less code. Now as you can image there are more additions to Framework 3.0, but in this I wanted to focus on the large ones that will make your life as a programmer much easier, and allow for faster deployment of applications. I hope you found this tutorial useful and informative, and thank you for reading.

Happy Coding!

Build an effective portfolio in Freelancing

Nykc — Fri, 21 Nov 2008 12:56:58 -0700

Everybody in the industry be it graphics design, web developers and coder's alike should all have some sort of portfolio to show clients. What are some of the creative ways you built your portfolio.

I am in the process of building mine up but usually combine both a webpage and a notebook with print media samples. I created some menu's for restaurants and newsletters etc..

One creative way is to buy some cheap USB drives and hand those out to potential employers.

Discuss...

iPhone language support in Software Development

fooboo — Fri, 21 Nov 2008 08:31:47 -0700

I'm looking into what it takes to develop for the iPhone. All I can find so far is info on how to make iPhone compatible web pages.

Does anyone know what languages the phone supports (j2me? C++?) for native apps not web pages?

Coding Standards, do most employers have them in Corner Cubicle

maffelu — Fri, 21 Nov 2008 06:08:11 -0700

Hi!

I was wondering what the standards are when you get a job as a C# programmer as to structure in C#. I've gone through alot of structural changes in my way of coding the last 6 months(starting of at the spagetthi-stage).
Right now, I put almost all of my codes in classlibs and almost no code in my forms(when working with forms). When a button was pressed in my old programs, I had basically all my code under the button event, but now I have almost no code there, just pointers to other classes where the code is.

What's the rule? Where should the code be placed in a program /rolleyes.gif" style="vertical-align:middle" emoid=":rolleyes:" border="0" alt="rolleyes.gif" />

Failing Economy and the IT Sector in Corner Cubicle

musya — Thu, 20 Nov 2008 16:07:05 -0700

The point of this poll is to see if an economic downturn would effect the IT industry and how much, and more speciffically which which areas of expertise. Many of us know the economy sucks dow closed around 7500 today. So take the poll and we'll see whats going on out their in the IT world economy. If you know of anything good to add on to this just post it.

Thanks,
Musya

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