I had encountered the following message, “System.FormatException: String must be exactly one character long..,” when I try to query an object as shown in the following code.

DataClasses2DataContext dataContext = new DataClasses2DataContext();
document doc = (from d in dataContext.documents
                                   where d.COST_ID == “xxxxxxxxxx”
                                  select d).First<document>();

For your information, I created the entitiy classes (e.g. document) by dragging a table from Server Explorer into the Designer. Visual Studio 2008 generated an entity class (including c# and xml files)  automatically.

Based on reported bug discussed in Microsoft website, I found out the problem. I discovered that a data type defined in xml (dbml) file was System.char for a NVarChar(1) column in the database; whereas, the data type defined in the auto-generated entity class is String. The solution is to change the “System.char” to “System.string” in the dbml (xml) file.

I had heard about ABAP for a long time. I knew that it is a programming language used in the SAP system. I did it once when I was studying the SAP BW module. I think that I should give it a try. I had seen that some companies want to hire an ABAP programmer. I am currently looking for a job. Let’s do some ABAP studying.

I started reading from the book called  “Introduction to ABAP/4 Programming for SAP, Revised and Expanded Edition.” Interestingly, I found out that ABAP is used for 2 cases mostly. First, ABAP is used to generate report from data within the SAP system. Second, ABAP is used as an interface for import data from an external systerm into the SAP system.

I was watching Celebrity Apprentice II. There were two teams: girls team and boys team. They had to sell a wedding dress. The team that makes more money wins. It is quite obvious that the girls team has an advantage. One of the girl had a wedding before, and she got her wedding stylist to help her.
Additionally, both teams have to pick 125 wedding dresses from a wedding store for free to sell. The girls team picked the expensive dresses, while the boys team picked the cheap dresses. One of them in the boys team said something like “due to current economic, people would buy the cheap one.” It made me to think, “don’t the teams get the dresses for free.” Then, later on, I found out that both teams’ strategy is to call their friends to come in and buy. The boys team should have picked the expensive dresses at first, so it is easier to ask someone to buy.

For the boys team, Tom Green got to be a project manager. I am quite wondering what Dennis Rodman is doing. He wanted to promote the wedding dress selling event, but he walked around in the neighborhood. In the end, the girl team made more money and won.

I just bought a mac computer.  It is a Apple MacBook Pro 13.3-Inch Laptop (2.26 GHz Intel Core 2 Duo) as shown below.

my MacBook Pro 13.3 inch

Previously, my sister had bought a iMac 20-inch as shown below. I love it as well. My mom currently uses the iMAC. Because I move around the house so much to find a comfortable and quite place, so I bought the Macbook Pro. If you are serious on using Mac for your work, and you have a good place where you work here all the time. I would recommend you to get the iMac 24-inch, because the screen is so big.

Apple iMAC 20 inch

There are some reasons that I want a Mac computer.
1. Ease of software development

I wanted a Mac computer, because I felt that it is easy to do a software development; for example, some tools come configured in a Mac computer already which I can access through a Terminal (kind of  DOS console in Windows) e.g. svn, ssh, ant, gcc, etc. I remembered that I had to spend time setup or configure to use those tools on Windows. Additionally, the Terminal in Mac is Unix-like, so I can practice my Unix skills e.g. how to use VI or grep command, and I can use those skills on a Linux which is Unix-like as well.

I have never used a Unix. You may wondering what does the term “Unix-like” mean. Both Linux and Mac behave the same as a Unix; for example, they use the same shell command e.g. cd, pwd, grep, ps, etc.
Shell is important, because it is more stable than GUI. Being able to manage a lot of thing via shells is good.

2. Special program on a Mac
MacTex is very easy to use as well. I remembered when I use TexMaker to edit a Latex document. I remembered that I use TextMaker on a Windows. A TexMaker would display a document in a PostScript viewer which is friendly to use. I can see one page at a time. I just could not do quick browsing. Then, I configured my TextMaker to convert the Latex document into  a PDF file and use the Acrobat Reader. The good thing is that I can browse through a PDF document very quickly, but the bad side is that I have open the PDF file manually. With MacTex (available only in Mac, the PDF is opened automatically, and I can skim through a document pretty quickly.

3. Mac software (iLife)
You do not need to buy a Mac. You can buy a Linux as well, and it is cheaper. However, there are good things about Macs over a Linux. There are some entertainment tools, multimedia content editing, and other tools which are not available on a Linux. For example, I really like the iTune, iPhoto, and iCal. I don’t know much about the multimedia content editing (e.g. GarageBand), because I have not played around with it yet. I will talk about it in the future post.

4. Hardware
It is difficult to connect a monitor through a laptop in a regular PC (Windows or Linux). Mac has a special port which can be plugin easily to a second monitor.

Volkswagen Ads

“Schade, dass man nach Amerika nicht fahren kann” probably means “what a pity that a man can not drive to America.” At first, I thought that it meant “what a pity that a man can not travel to Americal” which does not make sense, because a man can travel to America by an airplane. The important verb word here is “fahren” which means “travel.” Then, I realized that the “fahren” word could mean “drive” as well. Then, it made sense to me.

My experineces regarding the use of new language.

German

1) Last month, I was in the terminal in Frankfurt airport. The airplane was late for 2 hours, so the airline  gave the passengers snacks and drinks. The airline also brought a big shelve of magazines. I heard, “Alles muss raus,” so I though they meant, “everything must go.” I went to take a lot of magazines, but then I realized that they meant, “everyone get out.” The ground workers were clearing the passengers to move out from the gate area. The ground workers wanted to check tickets of each passenger before the passengers can move into the gate area.

At first, I thought that they mean, “everything must go,” because they put out snacks, drinks and magazines. I remembered that when a store is closed, a sign written “alles muss raus”  is put in front of the store to advertise goods.

2) The word “Sie”  in German has many meanings. “Sie,” when starting a sentence,  could mean “they”, “you,” or “she.” I was speaking to one teacher telling her about my friends, and the teacher talked to me and used the word “Sie.” My German was very weak back then. I was not sure what the exact meaning that she meant. If I could catch the form of the verb used, I might be able to determine the exact meaning, so I asked back something like, “You mean Sie (you) or Sie (they). 

English

1) When I was a kid, I saw a westener come toward me and asked me if I can speak English. At that time, I just came out from the English course. I answered him, “yes.” However, after that I did not understand what he said. It’s quite funny. I should have said, “no.”

Last semester of my master study, I had taken the SAP online course from U. of Duisburg-Essen called, “Introduction to SAP BW/SEM (Einführung in SAP BW/SEM)” focussing on SAP BW and SEM modules.  This course is no longer offered anymore, but there is a new course called, “Introduction to SAP BI (Einführung in SAP BI)” focussing solely on SAP BW.

 The cost of the course is 450 EUR. It was a lot of money for me. I think that it would be more expensive If I am not a student. Anyway, I could experience and learn the SAP while I was a student. 

About about my experience taking this course, I liked the course. Students are required to complete exercises even though there are solution or answers to the exercises. I have an opportunity to learn the basic of  BW (Business Warehouse) and SEM (Strategic Enterprise Management) modules. There are scripts which contain the theory part and the practical part mixed together used by students to study at their own pace. 

The course is German. I moved slowly at the beginning due to my weakness in German. I spent sometimes opening a dictionary and translating text. It paid off well later. I spent less time opening a dictionary and translating text later.

For BW module, I have known the data warehouse concept before from my bachelor, so it helps me to quickly understand the theory part including data cube and star schema (kind of a design of tables in a data warehouse). The theory part is partially based on or similar to the “Data Warehousing mit dem SAP Business Information Warehouse“ theory script from Technical University of Munich (Technische Universität München). For the practical part, it was quite frustrating in the beginning to learn about various terms used in SAP BW including transfer structure, communication structure, data source, info source, data object, update rule, transfer rule, etc. Anyway, I was glad that I could overcome it and finish the course. You may read the “SAP BW Grundlagen (p. 29)” slides in German which is useful for explaning terms used in SAP BW.

I learned deutsch (German) today. It is better for me to write it down, so I do not forget.

1)  word + word

There are some words in Germany built by combining other words. For example, the “züruckbezahlen” (pays back) word   consists of two words: “zurück” (back) and “bezahlen” (pay). This word is listed in dictionaries. However, there are some combined words  not listed in dictionaries which could be quite frustrating for a new beginner when he or she can not find the combined word meaning from dictionaries.

There are words which have different meanings when combining it together. For example, the “sitzen bleiben” means to sit on the chair, and “sitzenbleiben” means to repeat the course in the school again.

There is a joke. There are two sentences. Words are the same. They are written a bit differently. They have different meaning. 

- Ich gehe in die Klasse, um dort sitzen zu bleiben. (I go into the class just to sit there.)

- Ich gehe in die Klasse, um dort sitzenzubleiben. (I go into the class to review the learned material again there)

A kid may say that I am going into the class just to sit there, but their parents may though that their child goes into the class to study. 

2) word + one character + word

Sometimes, two words are connected together with a single character. For example, the “Wirtschaftskrise” (Economic crisis) has a character “s” in the middle to connect “Wirtschaft” and “Krise.” The actual meaning is “Krise der Wirtschaft” (Crisis of the econimic). If you understand genitiv, then you would understand the function of the article “der” here which means “of.”  Another example is “Wirtschaftslage” (“Lage der Wirtschaft,” Situation of economic).

First of all, I am not an expert in economic. I just write what I think. It maybe incorrect.

I remembered that I attend the Informatics Entrepreneurship II course, and there was a student asking a teacher about how could the music industry deals with the copyright infringement problem. The music industry was losing money, because people do not buy their CDs. The guest speaker introduces the concept of scarce and abundance. At any given time for something, there are something a little (scarce), and there are something a lot (abundance). For example, for the music industry, the abundance is the music available from the Internet, and the scarce could be the concert ticket.

In my opinion, it is necessary for an entrepreneur to detect what is scarce and abundant. I agree with the guest speaker on the scarce and abundance concept. 

In 1997, there was  an economic crisis in Thailand. Before the crisis, the real estate was bubble. People bought real estate (houses or land) for investment, but they did not buy real estate for living or do something. They hoped that the prices would increase. The prices of real estate were indeed increased. However, after the economic crisis, the prices drop significantly. People do not have money to pay back to the bank. When people can not pay back, the banks took the real estate properties. The abundance would be a lot of cheap real estate. The scarce would be the money. If anyone had bought the cheap real estate properties at that time, they could sell at very high price now, because the real estate business has improved. The situation is similar to the credid crisis occurred in USA recently. If any one has money, they can buy a house cheaply. 

If I remembered correctly, the guest speaker also mentioned about the situation in 2001 for IT companies. A lot of companies laid out software developers. Abundance would be the programmers. If anyone with money, they can start an IT company cheaply by hiring those laid out  programmers cheaply. When the economic is back, they can sell their IT products.

I had read the Microsoft Windows Workflow Foundation Step by Step book.  Overall, it is a good reference book.

However, I am not quite sure about the application example illustrated in the Microsoft Windows Workflow Foundation Step by Step book in “External Data Communication” section. The example may not illustrate the true purpose of using the correlation parameter.

The example is about a process of a truck. One workflow has only one truck. There could be many workflows in the system. Each workflow has one truck ID. A truck ID is part of the correlation parameter. 

Perhaps, I am wrong. It seems to me that the application try to use the truck ID to differentiate different workflows, so the runtime could send the message to the correct workflow.  I think that the runtime uses Guid which is a workflow instance ID stored in the EventArgs object. The EventArgs is created when the runtime fires an event to the workflow. This Guid is used to differentiate between different workflows, but not the correlation parameter.

Activities in the same conversation are chained together through the value of the correlation parameter.  A better example of using the correlation parameter could be that there are many tasks running parallel in a workflow. Note, this example could be found in my previous blog, “Communication Between Inside And Outside Of A Workfow In Windows Workflow.” Each task sends a request and waits for response. Each task has uniquely Task ID. The response sent by task 1 would go back to task 1. The response sent by task 2 would go back to task 2. In this case, there are two values of Task ID which are 1 and 2. The example found in the book simply has  only one Truck ID for the whole workflow which is not make sense.

I think that the objective of the correlation parameter is to bring back an event from outside to the correct activity in a workflow, not to bring back an event to the correct workflow.