Definition #1
A data warehouse is a system that retrieves and consolidates data periodically from the source systems into a dimensional or normalized data store.
Definition #2
A Data Warehouse is a database that is designed for facilitating querying and analysis. These database contain read-only data that can be queried and analysed.
Conclusion:
So what is difference between database and data warehouse?
Database is designed to record data and Data Warehouse is designed to analysis data.
Monday, April 9, 2012
Monday, April 2, 2012
The best way to planning software
I believe Use Case diagram, Entity-Relationship model and flowchart to design a software. It is extremely useful because I loose less time to program and correct the mistakes. I would rather planning during two months than programming during two months. Why? Because a software with good planning is cheap, fast and flexible unlike a software with bad planning that is expensive, slow and inflexible to possible changes.
All my academic life, I got used to program more hours than planning. My works were not awesome but also were not bad. It was enough to pass in evaluation. Finishing my course, I did an internship at the software company. Bringing old habits, I programmed more than planned. I had a project to finish in beginning of December but I finished in end of January. Why? Bad planning! My boss was angry with me for I did not meet deadline. I confess that is not good to see my boss angered!
I learned a lot with that mistake. From that, to develop any software, I always make Use Case diagram, Entity-Relationship model and flowchart. Use Case diagram is very abstract and easy to understand what the actor's goal. Entity-Relationship is used to define tables on database. Without this model, I would be lost. The flowchart is used to define software's logic.
With those three tools of planning, I spend less time to program, more time to planning, I am able to meet deadline and my boss will be happy with my work.
Wednesday, March 21, 2012
Communicating between PC and Arduino (Correction)
On March 19th, 2012, a youtube user called Sophie333C found a problem on video "Communicating between PC and Arduino".
Sophie333C's comment:
Hi, There seems to be a problem when you press send the second time around,
it only seems to update every second press of the button!
After two days, she sent me a solution. I tested her solution and it works fine. Now I can receive a answer
when I press the button for first time. Here is code of solution:
answer = port_arduino.ReadByte()
TextBox2.Text = Chr(answer)
I would like thank to Sophie333C to found out this problem.
Monday, March 12, 2012
Processing Language
Processing is for writing software to make images, animations, and interactions. The idea is to write a single line of code, and have a circle show up on the screen.
Code:
void setup(){
size(480,120);
ellipse(50,50,60,60);
}
}
The size(width,height) function has two parameters: the first sets the width of window and the second sets the height of window.
The ellipse(x,y,width,height) function has four parameters: the first sets the x-coordinate of center, the second sets the y-coordinate of center, the third sets the width of ellipse and fourth sets the height of ellipse. The x and y coordinates for ellipse are the center of the shape. Processing doesn't have separate functions to make circle. To make this shape, use the same value for the width and the height parameters to ellipse().
Tuesday, March 6, 2012
Problems with jQuery and Internet Explorer
I had a problem with jQuery when I opened Internet Explorer. I couldn't see Date Picker!
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<script type="text/javascript" src="js/datepicker-2.6.js"></script>
<script type="text/javascript" src="js/jquery-1.7.min.js"></script>
<title></title>
</head>
<body>
<input id="date" name="date"/>(dd/mm/yyyy)
<script type="text/javascript" >
var dp0 = new DatePicker("#date",{format:"d/m/Y",displayWeekNumbers:true});
</script>
</body>
</html>
To correct the problem, you have to add the next statement: <meta http-equiv="X-UA-Compatible" content="IE=edge"/>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<script type="text/javascript" src="js/datepicker-2.6.js"></script>
<script type="text/javascript" src="js/jquery-1.7.min.js"></script>
<title></title>
</head>
<body>
<input id="date" name="date"/>(dd/mm/yyyy)
<script type="text/javascript" >
var dp0 = new DatePicker("#date",{format:"d/m/Y",displayWeekNumbers:true});
</script>
</body>
</html>
To correct the problem, you have to add the next statement: <meta http-equiv="X-UA-Compatible" content="IE=edge"/>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="X-UA-Compatible" content="IE=edge"/>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<script type="text/javascript" src="js/datepicker-2.6.js"></script>
<script type="text/javascript" src="js/jquery-1.7.min.js"></script>
<title></title>
</head>
<body>
<input id="date" name="date"/>(dd/mm/yyyy)
<script type="text/javascript" >
var dp0 = new DatePicker("#date",{format:"d/m/Y",displayWeekNumbers:true});
</script>
</body>
</html>
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