Tag Archives: Typed Dataset

Typed DataSet

Typed DataSet includes Type-safe into Dataset fields so as to protect it from runtime mismatch. These classes inherit directly from DataSet class.

eg: Runtime error using normal Dataset

1. Using DataSet:

 //Create DataAdapter

SqlDataAdapter daEmp = new SqlDataAdapter(“SELECT empno,empname,empaddress FROM EMPLOYEE”,conn);

//Create a DataSet Object

DataSet dsEmp = new DataSet();

//Fill the DataSet

daEmp.Fill(dsEmp,”EMPLOYEE”);

//Let us print first row and first column of the table

Console.Write(dsEmp.Tables[“EMPLOYEE”].Rows[0][0].ToString());

//Assign a value to the first column

dsEmp.Tables[“EMPLOYEE”].Rows[0][0] = “12345”;//This will generate runtime error as empno column is integer

  2. Using Typed DataSet:

 //Create DataAdapter

SqlDataAdapter daEmp = new SqlDataAdapter(“SELECT empno,empname,empaddress FROM EMPLOYEE”,conn);

//Create a DataSet Object

EmployeeDS dsEmp = new EmployeeDS ();

//Fill the DataSet

daEmp.Fill(dsEmp,”EMPLOYEE”);

//Let us print first row and first column of the table

Console.Write(dsEmp.EMPLOYEE[0].empno.ToString());

//Assign a value to the first column

dsEmp.EMPLOYEE[0].empno = “12345”;//This will generate compile time error.

 Typed dataset is very much similar to a normal dataset; the only difference is that the schema is already present for the same. And any mismatch in the column will generate compile time errors rather than runtime error as in the case of normal dataset. Also accessing the column value is much easier than the normal dataset as the column definition will be available in the schema.

  Typed DataSet can be generated in two ways,

 1) Using Visual Studio .NET IDE.

2) Using XSD.exe (Using VS.Net command prompt)

Open VS.Net command prompt and Type XSD /? For the help on this exe.

 Creating a Typed DataSet using Visual Studio .NET IDE

 Let me explain a step by step procedure to create a Typed DataSet,

 1. Open VS .Net IDE and Click on File -> New -> Project and Select Console Application.

2. Enter name for the project. Say TypedDataSetTest.

3. Right click on the solution and click on Add-> Add New Item will show a dialog box.

Select DataSet from templates pane, give the name (Say TypedDs.xsd) and click on Open. This will add file by name TypedDs.xsd to the solution.

4. Click on the Server Explorer browse to the database and drop the table on the TypedDs.xsd file. 

If we check the xml file for the same then we can see the schema for the table.

This dataset can be used in the same manner as the normal dataset to get the data.

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