Tip: For examples on how to create ActiveX value objects, see the DataBlade Developers Kit InfoShelf, described in "The DataBlade Developers Kit InfoShelf" of this manual's introduction.

ActiveX Value Objects

An ActiveX value object is:

• the client-side encapsulation of an opaque type and its support routines retrieved from an Informix database server, for use by a client application developer.
• a Microsoft Common Object Model (COM)-compliant object; that is, a self-contained binary object that provides standard interfaces to its callers.

Client and Server Projects

• Client project. An ActiveX value object; that is, a client-side interface to an opaque type and its support routines.
• Server project. An opaque type and its support routines that you intend to encapsulate as an ActiveX value object.

Important: Object persistence between server and client objects is not supported. In other words, although you can modify an ActiveX value object, an associated modification does not occur to the database data represented by that object unless you issue an SQL query.

BladeSmith can generate the client and server projects for you at the same time. The client project is generated in C++ and must be implemented in C++. However, you can choose to generate and implement the server project in C++ or C.

The following table describes the advantages and disadvantages of each language choice.

Server Project Language	Advantages	Disadvantages
C++	Much of the source code that compiles the client project can also be used to compile the server project.	C++ can be used only in opaque type support routines. If your project includes other DataBlade module objects, they must be implemented in C. To define other DataBlade module objects, follow the instructions in Chapter 3, "Using BladeSmith."
C	If your project includes other DataBlade module objects, then all server code can be implemented in the same language (C). You do not need to concern yourself with the limitations and restrictions of using C++ in code that runs on the server.	The source code that compiles the client project cannot be shared with the server project. In addition to generating and implementing the client project in C++, you must generate and implement the server project in C.

Figure 6-1 illustrates the advantage of choosing C++ for both the client and server projects: much of the same generated source code can be used to compile each project.

Figure 6-1 Choosing C++ for Both Client and Server Projects

Creating ActiveX Value Objects Overview

To create ActiveX value objects using the DataBlade Developers Kit, complete these general processes:

1. Design the ActiveX value objects (see "Designing ActiveX Value Objects").

1. Use BladeSmith to define the opaque types that you intend to encapsulate as ActiveX value objects (see "Defining the Underlying Opaque Types").

1. Use BladeSmith to generate source code for the client and server projects (see "Generating Source Code for the Client and Server Projects").

1. Use a text editor to implement the client and server projects by adding project-specific logic to the generated source code (see "Implementing ActiveX Value Objects").

1. Use your software development environment to compile the client and server projects (see "Compiling Client and Server Projects").

1. Use your software development environment to test and debug the client and server projects (see Chapter 8, "Testing and Debugging DataBlade Modules on UNIX" and Chapter 9, "Testing and Debugging DataBlade Modules on Windows NT").

1. Use BladeSmith to regenerate source code for the client and server projects (see "Generating Source Code for the Client and Server Projects")

1. Use BladePack to package your client and server projects for distribution (see "Creating an Installation Package").