compare.c

一个用C编写的简单的关系数据库系统

int Compare(RecUnion * x, RecUnion * y, int typeX, int typeY)
{
	if (typeX != typeY)
	{
		puts("	输入条件错误，类型不符，不能进行比较");
		return ERROR;
	}
	switch (typeX) {
	case Int:
		if (x->intType - y->intType == 0)
			return EQ;
		else if (x->intType - y->intType > 0)
			return GT;
		else
			return LT;
	case Float:
		if ((x->floatType - y->floatType <= 0.00001) && (x->floatType - y->floatType >= -0.00001))
			return EQ;
		else if (x->floatType - y->floatType > 0.00001)
			return GT;
		else
			return LT;
	case String:
		if (strcmpi(x->string, y->string) == 0)
			return EQ;
		else if (strcmpi(x->string, y->string) > 0)
			return GT;
		else 
			return LT;
	}
	return ERROR;
}