Summary
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Over the years since programmers have been writing programs, various techniques have evolved that allowed programmers to write code that can be shared from program to program.
The first type of code sharing was a simple library of code containing common routines that could be copied into programs. This worked well until a bug appeared in the common routine; then all the programs that used that routine needed to be recompiled.
To solve the recompilation issue, dynamic libraries of code were created. The library was precompiled and a program simply referenced the code in the library and used it. If the dynamic library changed, all programs that referenced that library were automatically updated because the code was not statically copied into the program but rather loaded dynamically when the program ran. This type of reuse was limited to code only.
Object-oriented techniques were invented that allowed both code and data to be placed in a reusable object. Since objects contain both data and code, they really have everything a program has and can represent real-life entities like customers or reports.
OO programmers introduced the following terminology to describe entities:
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Methods describe what an object can do; methods behind the scene are subroutines and functions in the object.
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Properties describe the characteristics of an object; behind-the-scene properties are variables and data in an object.
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A special collection object contains references to other objects. Collections can be considered an array of objects.
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Object model diagrams illustrate the relationship between one object and another in complex systems.
Crystal Reports exposes it functionally through objects, so it is imperative to understand OOP concepts in order to effectively use Crystal Reports in a custom application.
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EAN: 2147483647
Pages: 217