CRM Metadata

Metadata is defined as data about data. MS Dynamics CRM uses a metadata driven architecture to provide the flexibility to create custom entities and additional system entity attributes.
MS Dynamics CRM retrieves the record data from the metadata (entities, attributes, relationships, and option sets.), which in turn retrieves information from the underlying system data. MS Dynamics CRM stores its underlying system data in a relational database using Microsoft SQL Server.

MS Dynamics User Interface  ->  Metadata ->  Underlying System Data (SQL Server)

The entity metadata controls the grid and form layout, and how navigation options are presented. The metadata makes heavy use of MS Dynamics CRM Web services and XML data formats.

Make changes directly to CRM database in Microsoft SQL Server, risk of damaging the metadata and creating errors in your system.

C# - Program Structure, Data Types, Type Casting (Conversion)

Program Structure
//the using keyword is used to include the System namespace in the program.
using System;
//the namespace declaration. A namespace is a collection of classes. The HelloWorldApplication namespace contains the class HelloWorld.
namespace HelloWorldApplication
{
   //a class declaration, the class HelloWorld contains the data and methods
   class HelloWorld
   {
      // the mehod declaration
      void Print()
      {
//Comments
/*...*/
//
      }
   }
}
C# is case sensitive.
All statements and expression must end with a semicolon (;).

Data Types
Value types 
- value type variables can be assigned a value directly.
- bool, byte, char, decimal, double, float, int, long, sbyte, short, uint, ulong, ushort
- get the exact size of a type or a variable - sizeof(int)
Reference types
- The reference types do not contain the actual data stored in a variable, but they contain a reference to the variables. in other words, they refer to a memory location.
- Using multiple variables, the reference types can refer to a memory location. If the data in the memory location is changed by one of the variables, the other variable automatically reflects this change in value.
- object, dynamic, and String.
- object obj = 100; //it will assign ar comiple time
- dynamic d = 100; //it will assign at run time
- String s ="C# code"; or @"c# code";
Pointer types (Unsafe Codes)
- store the memory address of another type.
- char* cptr;

Type Conversion (Type Casting) -  converting one type of data to another type, 2 forms
  - Implicit type conversion
  - performed by in a type-safe
  - int i = 123456789;
   long l = il
  - Derived d = new Derived();
   Base b = d;
  - Explicit type conversion
  - conversions are done explicitly  by users using the pre-defined functions. Explicit conversions require a cast operator.
  - double d = 1234.67;
   int i= (int)d; // 1234
  - type conversion methods -   ToBolean, ToByte, ToChar, ToString()
  - int i = 75; i.ToString();