In my previous article, we discussed on how to generate XML document or XML stream from your dataset. There I mentioned that one of the major advantage of converting a dataset into XML is we can easily validate our XML data against the XML schema. The XML schema is used to define the format, data types and key constraints that you want to validate. The XML document or XML stream can be validate against the predefined XML schema and exactly you can get the validation error and on which tag that error is occurred.

First you need to have a XML document to validate. There are several ways to convert your data into XML documents. In previous article I showed you one such method. In this article I will show you how to do a validation with XML schema for existing XML document.

XML data definition format is heavily used in nowadays applications since it is very rich data definition method. Working with XML data is very customizable, easy and reliable. Important features of XML language are;

• well defined schema
• purely character based data definition method
• customizable tags
• easy validation of XML documents

In ASP.NET it provides lot of shortcut methods to work with XML data. Actually .NET Frameworks most of the components fully based on XML languages. Few examples are Data Grid, Data Set and Class Designer etc. Due to this reason you can easily convert data in dataset to XML document and read data from XML document to feed into dataset. Why it is important to convert dataset into XML documents is a good question to analyze. There are few reasons to explain here, first thing is dataset is a kind of a special data format and not exchangeable with different applications. Transfer through web protocols is not straight forward with dataset, but XML data is based on characters and easily pass through the network. Most importantly validation of data is very easier with XML data that data in dataset. There are buit in validation functions with XML documents in ASP.NET.

Using iSeries Navigator you can very easily specify Unique Key and Primary Key for database table in DB2 database. Most of the people are not well aware that DB2 is relational database and it support all the relational database concepts. I have experience that most of the developers are not using key constraints, referential integrity, triggers etc. But most importantly DB2 is support for all these features. Let's look at one by one how these concepts can be implemented using iSeries Navigator on DB2 database.

To create Unique Key or Primary Key for a given table you need to go the table definition. Right click on the table that you want to modify and add new key and select "Definition" option.

Fig 1: Table Definition Option

With Microsoft Visual Studio 2005 you can develop applications with Crystal Reports without using separate Crystal Report application installed in the development machine. They have provided Crystal Reports tool in standard toolbox in Visual Studio 2005 environment. Simply you need to drag and drop these controllers and develop your reports same as previously with Crystal Report. Advantage is you don't need to buy separate Crystal Report application and install them in development and deployment environments.


Fig 1: Crystal Reports Tools in Microsoft Visual Studio 2005

In conventional method it is not very straight forward to write stored procedures with DB2 in AS400 environment. You might need to remember lot of syntax or might need to refer books to find syntax to code the procedures. This is very inefficient method for today's database programming context. iSeries Navigator has been provided very cool feature to develop your stored procedures from the iSeries Navigator graphical UI. You don't need to remember all the syntax to write database coding and the tool itself given you all the syntax which are required to write your coding. Only you have to do is insert them into your coding and make necessary modifications.



Login to your iSeries Navigator and browse your database that you want to create new stored procedure and select "Procedures" section.

Fig 1: Select you database and Procedures in iSeries Navigator pane
Right click on Procedures and select "New" to create new stored procedure. There are two options to select either "SQL" or "External" type procedure to create. If you select ""SQL" you can write your new procedure using SQL syntax. Also you can use separate external program written using C, C++, CL, COBOL, COBOLLE, PLI, REXX, RPG, RPGLE and Java by selecting "External" option. This is very flexible method since high level programming languages are provided much more freedom to code complex coding than SQL language. This article is focus on develop a procedure using SQL language.

Fig 2: Create new SQL type procedure
Provide procedure name, description, maximum number of result set, data access and specific name in General tab of "New SQL Procedure" window.
Fig 3: New SQL Procedure General Tab

In Parameters tab you can specify what are parameters for the procedure. Click on "Insert" button to add new parameter, once you added new parameter you can change its name, data type, length and In/Out option.
Fig 4: New SQL Procedure Parameters Tab

Next step is develop SQL logic for the procedure. For that select "SQL Statements" tab in New SQL Procedure window. In SQL Statements tab you will have "SQL Statements examples" drop down list, Insert button and Statements section. From drop down list select what is the syntax that you want to insert into your code. This drow down list will show all the required SQL syntax to develop your SQL code. Once you select the statement, click on Insert button to enter selected statement into your code. After inserting default statement you can modify as you wish. For example you can change variable names, data types etc. Advantage here is you don't need familiar with all the syntax, but you can simply insert them and modify according to your requirement. You can put any number of statements to build up your SQL code.
Fig 5: New SQL Procedure SQL Statements Tab
In the above example I have inserted variable initialization and alter table SQL code. You can modify this inserted default code like below example.
SET myCounter= 4;
ALTER TABLE Customer ADD COLUMN Age INTEGER;
In first line I have initialized the variable called "myCounter" to 4. In second line I have alter the Customer table and add Age column.
In this way very easily you can develop your SQL program for your stored procedure. This is very efficient method and very time saving. But initially you might need to get little familiar with tool. Good luck and happy coding !

Sending an E-mail from your web site is really simple with ASP.NET. First of all will look at what actually happened when an E-mail is sending from a web site. First step is preparing your complete E-mail programmatically. For that you need to set source e-mail address, destination e-mail address, e-mail subject, e-mail body, SMTP (Simple Mail Transfer Protocol) mail server and SMTP port of your server. Once you prepare your E-mail in correct format, there is only one step to send the E-mail to your destination addresses. For that you need to pass the E-mail request to message queue of the SMTP server through SMTP port. By default port 25 is used as mailing port. That is only what you have to do and rest of the relaying of E-mail part will handle by the SMTP server itself. SMTP server is responsible to pass your E-mail to respective destinations.

System.Net.Mail namespace should import using following code.

using System.Net.Mail;

Code for prepare your E-mail format is as follows.

// System.Web.Mail.SmtpMail.SmtpServer is obsolete in 2.0
// System.Net.Mail.SmtpClient is the alternate class for this in 2.0
SmtpClient smtpClient = new SmtpClient();
MailMessage message = new MailMessage();

MailAddress fromAddress = new MailAddress(fromAdd, displayName);

// You can specify the host name or ipaddress of your server
// Default in IIS will be localhost
smtpClient.Host = "smtpsvr";

//Default port will be 25
smtpClient.Port = 25;

//From address will be given as a MailAddress Object
message.From = "fromadd@yourdomain.com";

// To address collection of MailAddress
message.To.Add("toadd@yourdomain.com";);

message.Subject = "Your E-mail subject";

// CC and BCC optional
// MailAddressCollection class is used to send the email to various users
// You can specify Address as new MailAddress("admin1@yoursite.com")
//message.CC.Add("ccadd1@yourdomain.com");
//message.CC.Add("ccadd2@yourdomain.com");

// You can specify Address directly as string
//message.Bcc.Add(new MailAddress("bccadd1@yourdomain.com"));
//message.Bcc.Add(new MailAddress("bccadd1@yourdomain.com"));

//Body can be Html or text format
//Specify true if it is html message
message.IsBodyHtml = false;

// Message body content
message.Body = "Your E-mail message contents";

// Send SMTP mail
smtpClient.Send(message);

Session timeout period can be set as you required simply changing web.config file of your web site. In ASP.NET web site once you add web.config file you can find tag. Inside this tag you can specify session timeout value. Add following code to your web.config file.

<system.web>
<sessionstate timeout="60"/>
</system.web>

In this example you have set sessionState timeout value to 60 minutes. You can change this value as you wish, but need to make sure that it is really required. For example if you set a very large value for timeout, your session will hang on forever in the server. This will lead some security issues, memory overflow issues and sometime unexpected behaviour of your web site. And also this value should not be very small values. For example if you have functions like uploading files in the web site, then you should give enough time to upload a file based on the size of the file, network traffic and bandwidth limitation of the client machine.

I lanched a new blog site for discuss about power electronics and robotics related topics. This site is intended to publish deep theoritical articles and practically implementations of power electronics and robot world.

http://www.elecsl.blogspot.com/

In Table go to Column tab and click on Add button to add new column. Specify column name, short name, data type text...etc. If you select numeric data type for you column you will see a check box "Set as identity column". Tick that check box to enable identity for this column. Once you check the check box it will expand the window which allow you to configure the identity settings.
Fig 2: Set as Identity Column

Set Increment to an any value that you want increment your identity value. If you set 1 here it will increase the existing maximum number by 1. Starting value is used to set increase first row. Minimum value and Maximum value are used to restrict the values to a particular range. Values to cache is used to load last maximum values to memory so that increase the maximum value by Increment value is not needed a database hit for read maximum value for the identity column. "Cycle values when the maximum or minimum value is reached" check box is used to set whether the repetative value range is necessary when the datatype is reached its maximum or minimum values. This option is not allowed if you have set the column as primary or unique key for the table. "Generate the values in the order requested" check box is used to set whether you need to set values for the column in order or not. For example if you delete any value in between the value range whether that value is reusable or not.
Once you set any column as identity you don't need to give values when you insert a record into table. This column will automatically will be filled by the DBMS itself.

Enter the schema name or search for a schema that you want to show in the navigator using "Select Schemas toDisplay" window. Add the schema to "Selected Schemas" list and click Ok.

Create New Schema
If you want to create a new database or schema, right click on Schemas and select "New -> Schema". Specify a name for the new schema, whether it needs to add to displayed list of schemas and create as standard library. "Create in" is the system pool that you want to create your database in. "Text" is to discribe shortly your database for operator's purpose.



Fig 5: New Schema Window

Create New Table
Once your database schema is listed under Schemas section, select the database that you want to work with. It will display all objects belong to the selected database such as aliases, constraints, distinct types, functions, indexes, journal receivers, journals, procedures, sequences, SQL packages, tables and views. Select "Tables" from the tree view and right hand side pane will display all the tables in the database. Right click on Tables and select "New -> Table" to create new table in the database.
Fig 6: Create New Table Window

In New Table window specify the table name, schema and system table name and text. System table name is used to identify the table in the system. Text is to describe the table purpose. Use "Volatile Data" check box if the table need to be volatile.
Add Column to Table
Fig 7: Create New Column Window
Specify Column name, Short name for system purposes, Data type, Text and Heading for new column. Data type drop down list shows all the data types that you can use for your purpose. Click "Add" once you enter all the details to add the column into table.

Finally you can bind the generated self-signed certificate to your secure SSL site by using "Bindings" link in actions pane for a selected web site.