The key is that * means for a reference to a type when at type declaration, but when we use it in a statement * means that we want the content that is referenced by the pointer. In the sample below,  *a means tha we want the content of the character at the memory at some address that is holded by the pointer a; and when we use a++ we want to move forward the addres of the pointer to the next character. Another thing to know is that when use the assignmente operator = , it returns the value just assgined, so when you type char x =  *a = *b; x will have the value just copied from b adress to a adress. Last but not least, the while operator is looking for some value greater than 0 in order to continue the loop. If you remember you C/C++ classes all the strings finishes with a '\0' character that is equal to 0 as an integer value. That´s why the while breakes at the end of the string, and that´s why it´s can be used to copy strings.

 Obviously you wont use this code in real life, but could be interesting for those you are not experienced on pointers.

unsafe
{
    IntPtr ptrA = Marshal.StringToBSTR("hola"); // Convert Managed String to Unmanaged char array
    IntPtr ptrB = Marshal.StringToBSTR("HOLA"); // Convert Managed String to Unmanaged char array

    char* a = (char*)ptrA.ToPointer(); // Reference to the first character of string "hola"
    char* b = (char*)ptrB.ToPointer(); // Reference to the first character of string "HOLA"
    char* start = a; // Keep reference to the first character

    while ((*a++ = *b++) != 0); // Do the strcpy

    string str = Marshal.PtrToStringBSTR(new IntPtr(start)); // Converto Unmanaged char array to Managed String in order to print
    Console.WriteLine("STRCPY Result {0}", str);
    Console.WriteLine("Press any key to continue...");
    Console.ReadLine();
}

We made a sample package named SBD with the procedure named TestProcedure:

Package Header:

PROCEDURE TestProcedure
(
    I_Parameter1 IN NUMBER,
    I_Parameter2 IN NUMBER,
    O_Parameter1 OUT NUMBER,
    O_Parameter2 OUT NUMBER
);

Package Body:

PROCEDURE TestProcedure
(
    I_Parameter1 IN NUMBER,
    I_Parameter2 IN NUMBER,
    O_Parameter1 OUT NUMBER,
    O_Parameter2 OUT NUMBER
) AS
BEGIN
   O_Parameter1 := I_Parameter1 + 1;
   O_Parameter2 := I_Parameter2 + 1;
END TestProcedure;

Then we create a SQL Server Stored Procedure to Wrapp the Oracle Store Procedure Invocation, the T-SQL inside the procedure for this sample is the following: 

DECLARE @l_i_parameter1 INTEGER
DECLARE @l_i_parameter2 INTEGER
DECLARE @l_o_parameter1 INTEGER
DECLARE @l_o_parameter2 INTEGER

SET @l_i_parameter1 = 5
SET @l_i_parameter2 = 10
SET @l_o_parameter1 = 0
SET @l_o_parameter2 = 0

EXECUTE ( 'begin SDB.TestProcedure(?,?,?,?); end;', @l_i_parameter1, @l_i_parameter2, @l_o_parameter1 OUTPUT, @l_o_parameter2 OUTPUT) AT DBLINK_NAME;

SELECT @l_o_parameter1, @l_o_parameter2

I Hope this sample ilustrate the concept. Also I want to mention that this sample only works with simple output parameters, if you are trying to query for resultsets I recommend to try the OPENQUERY statement insteed.

One of the biggest problems in data access object testing, are the unstable state of the underling data source and a lot of solutions emerge to fix this problem, like , mock objects, database transactions, compensation transactions, and so on. Plainly all those solutions require a little beat of effort and on some cases there is no possible to create a test case.

Hopefully COM+ technology in the version 1.5 presents a new kind of enterprise service called Services without Components, where you can use the services provided by COM+ without needing to build a ServicedComponent. By using COM+ services without components, we can avoid the overhead of creating a component that is used to access only the COM+ services we need to build our DAL unit testing.

The Unit Testing of Microsoft Quality Tools from Visual Studio 2005 provides a great framework from our integrated test development environment. It arrives with a set of custom method attributes that permit us to introduce some code at the initialization of the test, the test itself and at the end of test to cleanup the logic applied to the test. Obviously the idea was to provide a test framework that provides us the option to hook COM+ 1.5 services for our convenience.

The following code shows how easy is to enlist the component on a distributed transaction coordinated by the DTC.  At test cleanup we can abort the transaction to leave the data source in the same state prior to test execution.

[TestClass]

public class TransactionalTest

{

    [TestInitialize]

    public void Initialize()

    {

        ServiceConfig config = new ServiceConfig();

        config.Transaction = TransactionOption.RequiresNew;

        ServiceDomain.Enter(config);

    }

    [TestMethod]

    public void DatabaseOperationTest()

    {

        // Some CRUD operation

    }

    [TestCleanup]

    public void Cleanup()

    {

        if (ContextUtil.IsInTransaction)

        {

            ContextUtil.SetAbort();

        }

        ServiceDomain.Leave();

    }

}

I hope this brief explication can help on your test driven developments.

Happy coding!