insert.c

一个用C编写的简单的关系数据库系统

int Insert(DBF * dbf_name, char * commond, FILE ** opened_fp)
{
	RecUnion rec[MAX_FILED_COUNT]; 
	RecUnion * recIn = (RecUnion *)malloc(sizeof(RecUnion));

	int i = 0;
	int q = 0;/*循环变量*/
	int exist = TRUE;
	int xiaoshu = FALSE;

	unsigned j = 0;

	float div = 1;/*记录小数位数*10*/
	float tempFloat = 0;
	int fpi = -1;/*标记当前表在打开表数组中的号码*/

	commond = strtok(commond," ");
	commond = strtok(NULL," ");

	if (strcmp(dbf_name->dhName,"\0") == 0)
	{
		puts("	您还没有打开过文件,当前文件为空!!!");
		return FAILED;
	}
	i = 0;
	while (i < dbf_name->dhFieldCount)/*读取数据*/
	{
		if (commond == NULL)
		{
			printf("	格式错误，请输入 %s 属性 \n", dbf_name->dbf_struct[i].dhFieldName);
			return ERROR;
		}
		switch (dbf_name->dbf_struct[i].dhFieldType) {
		case Int:
			for (j=0; j<strlen(commond); j++)
			{
				if (!isdigit(commond[j]))
				{
					printf("	输入错误，%s 改为int型\n",commond);
					return ERROR;
				}
			}
			rec[i].intType = atoi(commond);
			break;
		case Float:
			for (j=0; j<strlen(commond); j++)
			{
				if (isdigit(commond[j]))
				{
					tempFloat = tempFloat * 10 + (int)commond[j] - 48;
					if (xiaoshu == TRUE)
					{
						div *= 10;
					}
				}
				else if (commond[j] == '.')
				{
					if (xiaoshu == TRUE)
					{
						printf("	输入错误，%s 改为float型\n",commond);
						return ERROR;
					}
					xiaoshu = TRUE;
				}
				else
				{
					printf("	输入错误，%s 改为float型\n",commond);
					return ERROR;
				}
			}
			rec[i].floatType = tempFloat / div;
			break;
		case String:
			if (strlen(commond) > (unsigned)dbf_name->dbf_struct[i].dhFieldLen)
			{
				printf("	输入字符串超出了定义的最大长度 %d\n",dbf_name->dbf_struct[i].dhFieldLen);
				return ERROR;
			}
			rec[i].string = (char *)malloc(dbf_name->dbf_struct[i].dhFieldLen * sizeof(char));
			strcpy(rec[i].string, commond);
			break;
		}
		commond = strtok(NULL," ");
		xiaoshu = FALSE;
		i++;
	}
	if (commond != NULL)
	{
		printf("	多余输入字符 %s\n",commond);
		return ERROR;
	}
	fpi = dbf_name->dhID;
	i = 0;
	fseek(opened_fp[fpi],sizeof(DBF),0);
	/*检查插入的记录是否已存在*/
	while (i < dbf_name->dhRecCount)
	{
		exist = TRUE;
		for (q=0; q<dbf_name->dhFieldCount; q++)
		{
			switch (dbf_name->dbf_struct[q].dhFieldType) {
			case Int:
				fread(recIn,sizeof(int),1,opened_fp[fpi]);
				if (rec[q].intType != recIn->intType)
					exist = FALSE;
				break;
			case Float:
				fread(recIn,sizeof(float),1,opened_fp[fpi]);
				if ((rec[q].floatType - recIn->floatType > 0.00001) || (rec[q].floatType - recIn->floatType < -0.00001))
					exist = FALSE;
				break;
			case String:
				recIn->string = (char *)malloc(dbf_name->dbf_struct[q].dhFieldLen * sizeof(char));
				fread(recIn->string,dbf_name->dbf_struct[q].dhFieldLen,1,opened_fp[fpi]);
				if (strcmpi(rec[q].string, recIn->string) != 0)
					exist = FALSE;
				break;
			default:
				break;
			}
		}
		if (exist)
			break;
		i++;
	}
	i = 0;
	if (dbf_name->dhRecCount == 0)/*插入的记录为第一个记录*/
		exist = FALSE;
	if (exist)
	{
		printf("	the record inputed already existed!!!\n");
		return FAILED;
	}
	/*插入记录*/
	fseek(opened_fp[fpi],0,2);
	WriteRec(opened_fp[fpi],dbf_name,rec);
	dbf_name->dhModify = 1;
	dbf_name->dhRecNO = dbf_name->dhRecCount;
	dbf_name->dhRecCount++;
	fflush(opened_fp[fpi]);
//	chsize(dbf_name->dhHandle, (filelength(dbf_name->dhHandle)+dbf_name->dhRecLen));
	/*free(recIn);
	recIn = NULL;*/
	return SUCCESS;
}