System.Data.SqlClient.SqlDataReader.SqlDataReader.GetSchemaRowType C# (CSharp) Method

		private void GetSchemaRowType (TdsColumnType ctype, int csize,
                                               short precision, short scale,
                                               out int dbType, out Type fieldType,
                                               out bool isLong, out string typeName)
		{
			dbType = -1;
			typeName = string.Empty;
			isLong = false;
			fieldType = typeof (Type);
			
			switch (ctype) {
				case TdsColumnType.Int1:
				case TdsColumnType.Int2:
				case TdsColumnType.Int4:
				case TdsColumnType.IntN:
				case TdsColumnType.BigInt:
					switch (csize) {
					case 1:
						typeName = "tinyint";
						dbType = (int) SqlDbType.TinyInt;
						fieldType = typeof (byte);
						isLong = false;
						break;
					case 2:
						typeName = "smallint";
						dbType = (int) SqlDbType.SmallInt;
						fieldType = typeof (short);
						isLong = false;
						break;
					case 4:
						typeName = "int";
						dbType = (int) SqlDbType.Int;
						fieldType = typeof (int);
						isLong = false;
						break;
					case 8:
						typeName = "bigint";
						dbType = (int) SqlDbType.BigInt;
						fieldType = typeof (long);
						isLong = false;
						break;
					}
					break;
				case TdsColumnType.Real:
				case TdsColumnType.Float8:
				case TdsColumnType.FloatN:
					switch (csize) {
					case 4:
						typeName = "real";
						dbType = (int) SqlDbType.Real;
						fieldType = typeof (float);
						isLong = false;
						break;
					case 8:
						typeName = "float";
						dbType = (int) SqlDbType.Float;
						fieldType = typeof (double);
						isLong = false;
						break;
					}
					break;
				case TdsColumnType.Image :
					typeName = "image";
					dbType = (int) SqlDbType.Image;
					fieldType = typeof (byte[]);
					isLong = true;
					break;
				case TdsColumnType.Text :
					typeName = "text";
					dbType = (int) SqlDbType.Text;
					fieldType = typeof (string);
					isLong = true;
					break;
				case TdsColumnType.UniqueIdentifier :
					typeName = "uniqueidentifier";
					dbType = (int) SqlDbType.UniqueIdentifier;
					fieldType = typeof (Guid);
					isLong = false;
					break;
				case TdsColumnType.VarBinary :
				case TdsColumnType.BigVarBinary :
					typeName = "varbinary";
					dbType = (int) SqlDbType.VarBinary;
					fieldType = typeof (byte[]);
					isLong = false;
					break;
				case TdsColumnType.VarChar :
				case TdsColumnType.BigVarChar :
					typeName = "varchar";
					dbType = (int) SqlDbType.VarChar;
					fieldType = typeof (string);
					isLong = false;
					break;
				case TdsColumnType.Binary :
				case TdsColumnType.BigBinary :
					typeName = "binary";
					dbType = (int) SqlDbType.Binary;
					fieldType = typeof (byte[]);
					isLong = false;
					break;
				case TdsColumnType.Char :
				case TdsColumnType.BigChar :
					typeName = "char";
					dbType = (int) SqlDbType.Char;
					fieldType = typeof (string);
					isLong = false;
					break;
				case TdsColumnType.Bit :
				case TdsColumnType.BitN :
					typeName = "bit";
					dbType = (int) SqlDbType.Bit;
					fieldType = typeof (bool);
					isLong = false;
					break;
				case TdsColumnType.DateTime4 :
				case TdsColumnType.DateTime :
				case TdsColumnType.DateTimeN :
					switch (csize) {
					case 4:
						typeName = "smalldatetime";
						dbType = (int) SqlDbType.SmallDateTime;
						fieldType = typeof (DateTime);
						isLong = false;
						break;
					case 8:
						typeName = "datetime";
						dbType = (int) SqlDbType.DateTime;
						fieldType = typeof (DateTime);
						isLong = false;
						break;
					}
					break;
				case TdsColumnType.Money :
				case TdsColumnType.MoneyN :
				case TdsColumnType.Money4 :
					switch (csize) {
					case 4:
						typeName = "smallmoney";
						dbType = (int) SqlDbType.SmallMoney;
						fieldType = typeof (decimal);
						isLong = false;
						break;
					case 8:
						typeName = "money";
						dbType = (int) SqlDbType.Money;
						fieldType = typeof (decimal);
						isLong = false;
						break;
					}
					break;
				case TdsColumnType.NText :
					typeName = "ntext";
					dbType = (int) SqlDbType.NText;
					fieldType = typeof (string);
					isLong = true;
					break;
				case TdsColumnType.NVarChar :
					typeName = "nvarchar";
					dbType = (int) SqlDbType.NVarChar;
					fieldType = typeof (string);
					isLong = false;
					break;
				case TdsColumnType.Decimal :
				case TdsColumnType.Numeric :
					// TDS 7.0 returns bigint as decimal(19,0)
					if (precision == 19 && scale == 0) {
						typeName = "bigint";
						dbType = (int) SqlDbType.BigInt;
						fieldType = typeof (long);
					} else {
						typeName = "decimal";
						dbType = (int) SqlDbType.Decimal;
						fieldType = typeof (decimal);
					}
					isLong = false;
					break;
				case TdsColumnType.NChar :
					typeName = "nchar";
					dbType = (int) SqlDbType.NChar;
					fieldType = typeof (string);
					isLong = false;
					break;
				case TdsColumnType.SmallMoney :
					typeName = "smallmoney";
					dbType = (int) SqlDbType.SmallMoney;
					fieldType = typeof (decimal);
					isLong = false;
					break;
				default :
					typeName = "variant";
					dbType = (int) SqlDbType.Variant;
					fieldType = typeof (object);
					isLong = false;
					break;
			}
		}