Advantages and Disadvantages of Dictionary Objects

Dictionary Object

Dictionary Object stores data key, item pairs. A Dictionary object stores the items in the array. Each item is associated with a unique key. The key is used to retrieve an individual item and is usually an integer or a string, but can be anything except an array.



Adavntages of using it in QTP:

1. can be used as Global variable declaration. so that any test can access the values from it in the run time.

2. You can store and retrive any number of run time values in to dictonary.

3. It is one of the Parameterization techique we can use in QTP



Disadvantages:

we can not specify the values in the desingn time like Datatable , Action parameters, environment variable.

So it is useful only in Run time , not design time

What is Dictionary Object - Overview

Dictionary object allows storing key value pairs. A dictionary object can be used for easy lookup of values. Dictionary is a not a QTP specific functionality and is available in normal VBScript as well.

Creating the Dictionary
A dictionary object can be created using CreateObject for COM class “Scripting.Dictionary”. The code below shows how to create the dictionary object in QTP


'Create the Dictionary Object
Set oDict = CreateObject("Scripting.Dictionary")


Below table shows list of methods that dictionary objects supports.
Method Description
Add (key, item)- Adds a key and item pair to a Dictionary object.
Exists(key)- Returns true if a specified key exists in the Dictionary object, false if it does not
Items() - Returns an array containing all the items in a Dictionary object
Keys() - Returns an array containing all existing keys in a Dictionary object.
Remove(key) - Removes a key, item pair from a Dictionary object
RemoveAll() - The RemoveAll method removes all key, item pairs from a Dictionary object.

Count - Returns the number of items in a Dictionary object. Read-only.
Item Sets or returns an item for a specified key in a Dictionary object. Read/write
Key(Key) Sets a key in a Dictionary object.

Adding Items to Dictionary:
There are two ways to Add items to dictionary. One is to use the Add method and another is to use the Item property. Both the methods are shown in code below
'Method 1 for Adding items to dictionary
'Add items to dictionary
oDict.Add "CA", "California"
oDict.Add "LA", "Los Angeles"

'The below line will throw an error as LA key already exist
oDict.Add "LA", "Los Angeles 2"

'Method 2 for adding items to dictionary
oDict.Item("CA") = "California"

'Item is the default property so ".Item" is not required
oDict("LA") = "Los Angeles"

'No Error this time as we are actually using the
'Item property and not the Add method
oDict("LA") = "Los Angeles 2"100 Miles From Memphis

Checklist for web services

Design Considerations

Design chunky interfaces to reduce round trips.

Prefer message-based programming over remote procedure call (RPC) style.

Use literal message encoding for parameter formatting.

Prefer primitive types for Web service parameters.

Avoid maintaining server state between calls.

Consider input validation for costly Web methods.

Consider your approach to caching.

Consider approaches for bulk data transfer and attachments.

Avoid calling local Web Services.
Connections
**********************************************************

Configure the maxconnection attribute.

Prioritize and allocate connections across discrete Web services.

Use a single identity for outbound calls.

Consider UnsafeAuthenticatedConnectionSharing with Windows Integrated Authentication.

Use PreAuthenticate with Basic authentication.
Threading
********************************************************************

Tune the thread pool using the formula for reducing contention.

Consider minIoThreads and minWorkerThreads for intermittent burst load.
One Way (Fire and Forget) Communication
**********************************************************************

Consider using the OneWay attribute if you do not require a response.
Asynchronous Web Methods
*********************************************************************

Use asynchronous Web methods for I/O operations.

Do not use asynchronous Web methods when you depend on worker threads.
Asynchronous Invocation
*********************************************************************

Consider calling Web services asynchronously when you have additional parallel work.

Use asynchronous invocation to call multiple unrelated Web services.

Call Web services asynchronously for UI responsiveness.
Timeouts
*********************************************************************

Set your proxy timeout appropriately.

Set your ASP.NET timeout greater than your Web service timeout.

Abort connections for ASP.NET pages that timeout before a Web services call completes.

Consider the responseDeadlockInterval attribute.
WebMethods
*********************************************************************

Prefer primitive parameter types.

Consider buffering.

Consider caching responses.

Enable session state only for Web methods that need it.
Serialization
*********************************************************************

Reduce serialization with XmlIgnore.

Reduce round trips.

Consider XML compression.
Caching
*********************************************************************

Consider output caching for less volatile data.

Consider providing cache-related information to clients.

Consider perimeter caching.
State Management
*********************************************************************

Use session state only where it is needed.

Avoid server affinity.
Attachments
*********************************************************************

Prefer Base64 encoding. Direct Internet Message Encapsulation (DIME) is a supported part of Web Services Enhancements (WSE), but Microsoft® is not investing in this approach long-term. DIME is limited because the attachments are outside the SOAP envelope.
COM Interop
*********************************************************************

Avoid single-threaded apartment (STA) COM objects.

VB Script - 3

Arrays

An array is a contiguous area in the memory referred to by a common name. It is a series of variables having the same data type. Arrays are used to store related data values. VBScript allows you to store a group of common values together in the same location. These values can be accessed with their reference numbers.

An array is made up of two parts, the array name and the array subscript. The subscript indicates the highest index value for the elements within the array. Each element of an array has a unique identifying index number by which it can be referenced. VBScript creates zero based arrays where the first element of the array has an index value of zero.

Declaring Arrays

An array must be declared before it can be used. Depending upon the accessibility, arrays are of two types:
• Local Arrays
A local array is available only within the function or procedure, where it is declared.

• Global Arrays
A global array is an array that can be used by all functions and procedures. It is declared at the beginning of the VBScript Code.

The Dim statement is used to declare arrays. The syntax for declaring an array is as follows:
Dim ArrayName(subscriptvalue)

Where, ArrayName is the unique name for the array and SubscriptValue is a numeric value that indicates the number of elements in the array dimension within the array.

Example:
Dim No_Passengers(3)
The No_Passengers can store 4 values.

Assigning values to the array
No_Passengers(0) = 1
No_Passengers(1) = 2
No_Passengers(2) = 3
No_Passengers(3) = 4

Static and Dynamic Arrays:

VBScript provides flexibility for declaring arrays as static or dynamic.
A static array has a specific number of elements. The size of a static array cannot be altered at run time.

A dynamic array can be resized at any time. Dynamic arrays are useful when size of the array cannot be determined. The array size can be changed at run time.
Next we will deal with user defined procedures, functions and subroutines.


This post is third in the VB Script and QTP series.

Here we shall talk about user defined procedures.

Procedures are set of executable statements.

In VBScript, there are two types of procedures:

Sub Procedures
Function Procedures




Sub Procedures

A sub procedure is a series of VBScript statements, enclosed by Sub and End Sub statements which perform actions but do not return a value. A sub procedure can take arguments. If a sub procedure doesn’t receive any arguments, its Sub statement must include an empty parenthesis().

The following Sub procedure uses two intrinsic, or built-in, VBScript functions, MsgBox and InputBox , to prompt a user for information. It then displays the results of a calculation based on that information. The calculation is performed in a Function procedure created using VBScript. The Function procedure is shown after the following discussion.

Sub ConvertTemp()
temp = InputBox("Please enter the temperature in degrees F.", 1)
MsgBox "The temperature is " & Celsius(temp) & " degrees C."
End Sub

Function Procedures

A function procedure is a series of VBScript statements enclosed by the Function and End Function statements. A function procedure is similar to a sub procedure but it can return value to the calling function. A function procedure can take arguments (constants, variables or expressions that are passed to it by a calling procedure). If a function procedure has no arguments, it Function statement must include an empty set of parenthesis. A function returns a value by assigning a value to its name in one or more statements of the procedure. Since VBScript has only one base data type, a function always returns a variant.

In the following example, the Celsius function calculates degrees Celsius from degrees Fahrenheit. When the function is called from the ConvertTemp Sub procedure, a variable containing the argument value is passed to the function. The result of the calculation is returned to the calling procedure and displayed in a message box.

Sub ConvertTemp()
temp = InputBox("Please enter the temperature in degrees F.", 1)
MsgBox "The temperature is " & Celsius(temp) & " degrees C."
End Sub

Function Celsius(fDegrees)
Celsius = (fDegrees - 32) * 5 / 9
End Function

Tips:
To get data out of a procedure, you must use a Function. Remember, a Function procedure can return a value; a Sub procedure can't.
AFunction in your code must always be used on the right side of a variable assignment or in an expression.
To call a Sub procedure from another procedure, type the name of the procedure along with values for any required arguments, each separated by a comma. The Call statement is not required, but if you do use it, you must enclose any arguments in parentheses.
The following example shows two calls to the MyProc procedure. One uses the Call statement in the code; the other doesn't. Both do exactly the same thing.

Call MyProc(firstarg, secondarg)

MyProc firstarg, secondarg

Notice that the parentheses are omitted in the call when the Call statement isn't used.