Tech Junkie Blog: March 2015

Tuesday, March 31, 2015

Resizing images is a common task that you have to do to show your photo image on a website.  Most digital camera or smart phones takes photos that are a lot larger than what most web sites can display in it's original size.  In this blog we will show you how to resize your photo in GIMP.

Step By Step Instructions:

1.  Open the original photo in GIMP

GIMP original photo size


Monday, March 30, 2015

Most new users to GIMP gets intimidated with the floating windows that is the default view when you first open GIMP.

GIMP default view


As you can see it is pretty intimidating, the majority of users sees this interface and runs back to GIMP's more expensive alternatives. Even though GIMP has most of the features of the more expensive softwares.   Most back end developers I encountered would hear good things about GIMP, download the software.  Get all excited about it, then when they first open it, their reaction is what in the world !@#$$$ (NC-17 censored) is this.  They would go back and use paint as their photo editor.  Which is a shame, because GIMP is quite powerful.

 However, there's a very easy solution to this UI dilemma and make GIMP more user friendly.

Step-By-Step Instructions:
  1.  Click → Windows → Single Window Mode
  2.  GIMP will dock all the floating windows into a single window, looking like all the other conventional programs that you are used to
GIMP Single Window Mode


Thursday, March 26, 2015

There are times when you see a class property without it's private member counterpart and all you see is the {set; get;} accessors. What you are looking at are auto properties that you can create  in C#, the only requirements is that the set; and get; accessors contains no logic.  Usually there are private members that the properties expose to other classes using the get/set accessors, like the code below:


    public class Product
    {
        private int productId;
        private string name;
        private string description;
        private decimal price;

        public int ProductId
        {
            get
            { return productId; }
            set
            {
                productId = value;
            }
        }

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

        public string Description
        {
            get
            { return description; }
            set
            {
                description = value;
            }
        }

        public decimal Price
        {
            get
            { return price; }
            set
            {
                price = value;
            }
        }

    }

The above class uses the regular ways you define properties that are exposed to other classes. Even though there are only get/set properties. The auto implemented version of the class requires a lot less typing.
    public class Product
    {

        public int ProductId { get; set; }
        public string Name { get; set;}
        public string Description { get; set; }
        public decimal Price { get; set; }

    }
The properties do not have be define as a private member of the class. This pattern is called the field-backed property pattern. This means that the C# compiler will take care of the private members fields for us when we build our classes. The above example are mutable properties, meaning outside classes can change the values of the properties.

Wednesday, March 25, 2015

In this blog I will go over how to set up jQuery for your web pages.  There are two methods to using jQuery.  The first is the use the CDN URLs that are hosted by jQuery, Google, and Microsoft just to name a few.  In this tutorial we will set the CDN from Google.  The process should be the same for jQuery and Microsoft CDNs.

Here are the URL for Google's jQuery Library:


1.x snippet: https://ajax.googleapis.com/ajax/libs/jquery/1.11.2/jquery.min.js

2.x snippet: https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js

You might be wondering why there are two versions of jQuery 1.x and 2.x, they both use the same APIs and they pretty much mirror each other on a release basis.  The only difference is that the 2.x versions does not support IE 6,7, or 8.  Just to be on the safe side I always use the 1.x versions.

Tuesday, March 24, 2015

Since Ubuntu does not configure the root account by default you have to manually assign root a password before you can use the root account.  However, there's a way to log in as "root" without setting up the "root" password.  The way to do this is to use the "sudo" and "su" command in combination.  The "sudo" elevates your privileges to root like priviledges, while the "su" command is used to switch from one user to another.  So when used together you get to log in as "root".

So in your Linux prompt type in the following command

sudo su

sudo su to log in as root





Monday, March 23, 2015

In the previous blog we went over how to create a simple ASP.NET MVC 4 application.  In this blog we will go over the steps to upgrade our ASP.NET MVC 4 application to ASP.NET MVC 5 application.

Step-By-Step Instructions:

  1. Open the "MyMVC4" project that you've created on the last blog
  2. Right click on the project and select "Manage NuGet Packages..."
Manage NuGet Packages















In this blog we will go over how to upgrade your existing project which uses ASP.NET MVC 4 to ASP.NET MVC 5 using NuGet.  During the upgrade you will encounter some errors but they are easy enough to fix by changing the Web.Config file.  In the first blog we will create a simple ASP.NET MVC 4 application from scratch.

But first thing is first let's begin by creating a project in ASP.NET MVC 4:

  1. Create a blank solution in Visual Studio call "MVCProjects"
Visual Studio 2013 Create New Blank Solution


Apache (HTTPD) is the most popular web server on the web right now.  It is from the Apache Software Foundation.  A web server serves content to the web.  The power of Apache lies in it's modules which allows you to process scripting languages such as Perl, and PHP.

In this blog we will go over how to install the Apache Http Web Server on the Ubuntu Server:

1.  In the terminal type in the following command

apt-cache search apache  | more

search for the latest apache web server version



the "search" command searches for the latest apache web server version, we added the "more" command so that we can press enter to scroll

Apache HTTP Server is called apache2















Sunday, March 22, 2015

There times when you have to store data as XML in a SQL Server database table.  In this blog we will go over how to store XML as data in SQL Server.  There's an xml data type in SQL Server that we can use to store XML data.

Example: Create a database table that contains a column to store XML data using the xml data type
CREATE TABLE Books
(
  Id INT NOT NULL IDENTITY(1,1) PRIMARY KEY,
  Book XML NOT NULL
);

If you look at the "Book" column for the table "Books" you will see that it has a data type of XML

XML Data Type In SQL Server

Now that we have our table set up, we can insert XML data to into the table

INSERT INTO Books(Book)
VALUES(
 CAST ( '<book>
  <author>Bill King</author>
  <title>ACME Consulting: An Inside Look</title>
  <publisher>ACME Publishing</publisher>
  <language>Swahili</language>
 </book>' AS XML));

In the example above we CAST the type to XML first before we insert the data into the Books column because we want to make sure that the data we are inserting into the column is a well-formed XML data. If you query the table now you will see that there's one record with XML data in the "Book" column

XML Data Type Results In SQL Server

Saturday, March 21, 2015


  WHILE SomeConditionTrue
    BEGIN
      -- Execute code here
    END

Friday, March 20, 2015



IF SomeCondition
  BEGIN
    -- Execute some code here
  END
ELSE
  BEGIN
   -- Execute some code here
  END
Else is optional

Thursday, March 19, 2015

Once you've graduated from the basic variables in JavaScript the next variable you want to learn is the JavaScript array.  An array is a group of variables in a list or collection.  However, you want to word it.  As with everything else a JavaScript array is mutable, meaning you can change it dynamically while you are working on it.

Declaring an Array
var alphabet = new Array();

alphabet [0] = 'A';
alphabet [1] = 'B';
alphabet [2] = 'C';

Declaring an Array In Literal Format
 
var alphabet = ['A','B','C']

Accessing Array Value
 
document.writeln("First Index: " + alphabet[0]);

Output:
First Index: A

Looping through an Array
 
for(var i = 0; i < alphabet.length;i++)
{
 document.writeln("index: " + i + " value: " + alphabet[i]);
}

Output:
index: 0 value: A index: 1 value: B index: 2 value: C

Wednesday, March 18, 2015

JavaScript objects acts differently than objects in the object-oriented programming world. A JavaScript object is mutable meaning it can be changed and is dynamic.

Here is how you would create a JavaScript object:

   var Employee = new Object();
    
   Employee.ID = 1;
   Employee.FirstName = "Jeff";
   Employee.LastName = "Jordan";
You create a new object the new Object() constructor
Or you can create a JavaScript object in a literal format
   var Employee = {
      ID: 1,
      FirstName: "Jeff",
      LastName: "Jordan"
};
You can also include a function as a method in your object like the example below
   var Employee = {
      ID: 1,
      FirstName: "Jeff",
      LastName: "Jordan",

      displayEmployee: function() {
          document.writeln("Employee ID: " + this.ID);
          document.writeln("First Name: " + this.FirstName);
          document.writeln("Last Name: " + this.LastName);
};


Tuesday, March 17, 2015

T-SQL variables allows you to store and assign values in your T-SQL code.  Variables is a storage unit in programming which allows you to refer back to it at a later time.

T-SQL variables have the following characteristics:
  • Local variables must be prefixed @
  • Global variables must be prefixed with @@
  • Must be declared with the DECLARE statement
  • Must specify the data type when declared
Declaring variables
    DECLARE @employeeID INT;
    DECLARE @firstName CHAR(10), @lastName CHAR(20);

As you can see from the above example you can declare a single variable or declare multiple variables with a comma separated list.

Setting variables

  SET @employeeID = 1;
  SET @firstName='Davolio';
  SET @lastName='Nancy';

The above example uses the SET statement assign values to the variables one at a time.

To assign values to multiple variables with one statement you can use the SELECT statement.
SELECT @employeeID=1,@firstName='Dovolio',@lastName='Nancy';

Convert INT Variable To String
 
  Convert(CHAR,@employeeID);

Monday, March 16, 2015

Start up your Linux machine then do the following:

  1. Press Ctrl + Alt + F2 to start a virtual console
  2. Login in with your credentials








3.  After logging in type "grep my-username-goes-here /etc/passwd", then you will see which shell environment you are using


Sunday, March 15, 2015

log4net is the most commonly used ASP.NET logging package.  It is robust and flexible in it's features.  You can choose to log your errors on the database or in a log file or multiple log files.  However, it is not as straight forward to set up.  In this blog we will go through the steps to install log4net using NuGet Package Manager.

1.  Create an empty web project, and call it whatever you like, below is the settings that I have, then click "OK"




2. Right click on the solution and select "Manage NuGet Packages for Solution..."


3.  Locate the search box on the left hand side


4. Type "log4net" in the search box, the latest log4net version will show up in the search results in the main window.  Click on the "Install" button.



5.  Select the project that you want log4net to be installed, then click "OK"


6.  After the installation under "References" log4net will be added

7.  

Saturday, March 14, 2015

If you've installed an operating system in VirtualBox before you've probably noticed the screen is really small even when you switch to Fullscreen mode.  It's so small that you can't even see the fonts for the icons if you have a desktop GUI installed.  To fix this problem VirtualBox provides us with the Guest Additions tool.  Which enables the virtual machine to be viewed at fullscreen.

To enable full screen on a Linux operating system.  Perform the following actions, this should work on all Linux distribution that VirtualBox supports.

1.  Start the virtual machine that you want to make full screen


Friday, March 13, 2015

The topic of installing a desktop GUI has been debated over the years.  Friendships have been ruined because of it.  I don't know if that's true, but some believe that the server should only have command line.  This blog is not about that debate, I just want to see some freaking graphics on the monitor, and for my mouse to be more than a paper weight.  So there's my opinion on the subject.

Anyways installing a GUI on Ubuntu server is really easy.

Here are the steps:

1. Start up your Ubuntu server VM

Thursday, March 12, 2015

In the previous two blogs we've gone through the steps to setting up the virtual machine to install the Ubuntu Server on VirtualBox, in this blog we will go over the steps to installing the Ubuntu Server. Be warn this is a long blog.  I usually try to break up my blog so that you won't doze off, but I feel like this one has be left in tack.  Here are the steps to install Ubuntu Server on your VirtualBox.

 1. Right click on the "Ubuntu Server" virtual machine and select "Start"






















Wednesday, March 11, 2015

In the last blog we've created a new virtual machine that is ready for a Ubuntu Server operating system.  Now we will install the Ubuntu Server operating system on that virtual machine. Here are the steps you need to take to install a Ubuntu Server operating system on that virtual machine.

1.  Right click the "Ubuntu Server" virtual machine, then select "Settings"


Tuesday, March 10, 2015

If you are a developer on a shoestring budget, Linux is the way to go if you want to compete with the big boys.  I have nothing against Microsoft, I actually love it a lot on the job.  But when you want to start a personal project, Linux is the way to go, to get the most bang for the buck.

Ubuntu has always been great at offering enterprise level server products for free.  A lot of what you learn with Ubuntu or any server side Linux distribution you can translate into the Windows environment quite easily.  So it's worth the effort.

But before you can do all that you need the Ubuntu server environment up and running.  Instead of going the dual boot route you can have your Windows OS as your main OS and run Ubuntu on a virtual machine, that's where VirtualBox comes in. So let's begin our journey into the world of enterprise Linux.

  1. First thing you need is the latest Ubuntu server distribution, you can get it here http://www.ubuntu.com/download/server 
    Ubuntu download page


Monday, March 9, 2015

Transaction processing is a concept in SQL that allows you to execute a query or rollback the changes if something goes wrong.  A way of enforcing the data integrity of the database.  As such, you can only rollback INSERT, UPDATE, and DELETE.  Not that there's any use in rolling back a SELECT statement because there's no change in data.

The following is how you would wrap a transaction around a DELETE statement:

BEGIN TRANSACTION
DELETE Products WHERE ProductID = 87
COMMIT TRANSACTION
The above query will only execute if there are no errors, if there's an error the transaction will be rolled back. That's it, that's the whole concept of what a transaction is, if there are no errors then you should get the following message.

(1 row(s) affected)

If you are dealing with multiple statements then you can use the SAVE TRANSACTION, SAVE TRANSACTION allows you to create a placeholder so that you can rollback a transaction at a checkpoint.

In the last blog we just selected the Products entities from the NorthwindEntities with this Linq Query.

var query = from prod in nwctx.Products
         select prod;

It gets the job done but, the GridView displays the CategoryID and SupplierID as integers, which is not very useful to your users. Plus, we don't want to display the ProductID.












Sunday, March 8, 2015

The SUM() function is used to sum up all the values in the specified column.

SELECT SUM(UnitsInStock) AS TotalInventory
FROM Products

The above query gets the total number of units in stock for all products

Wednesday, March 4, 2015

The SOUNDEX function is a cool function that you can talk about at your next dinner party. It searches for the words that sounds the same but are not. Like the query below, which queries product names that sounds like the word "Chief" in the Northwind Products table.

SELECT ProductName
FROM Products
WHERE SOUNDEX(ProductName) = SOUNDEX('Chief')

Monday, March 2, 2015

As you may have guessed the SQL mathematical operators are equivalent to their regular mathematical counter parts.

  1.  + Addtion
  2. - Subtraction
  3.  * Multiplication
  4.  / Division
Eamples:

1. Addition

SELECT UnitPrice, (UnitPrice + 20) AS RipOffPrice
FROM Products




Sunday, March 1, 2015

Concatenation means combining the value of two or more columns together to form a single value. The most common usage for this operation is to combine the first name and last name field. Like the query below.

  SELECT FirstName + ' ' + LastName AS Name
  FROM Employees

The query above concatenates the FirstName and LastName column from the Employees table in the
Northwind database and assign the alias Name to combined value.