数据库概述之数据库编程

/**
嵌入式SQL编程实例 
*/ 
EXEC SQL BEGIN DECLARE SECTION;//主变量说明开始
	char deptname[20];
	char hsno[9];
	char hsname[20];
	char hssex[2];
	int  HSage;
	int  NEWAGE;
EXEC SQL END DELCARE SECTION;//主变量说明结束
long SQLCODE;
EXEC SQL INCLUDE SQLCODE;//定义SQL通信区
int main(void)
{
	int coun=0;
	char yn;//变量yn代表yes或no 
	printf("please choose the department name(CS/MA/IS):");
	scanf("%s",&deptname);//为主变量deptname赋值 
	EXEC SQL CONNECT TO TEST@localhost:54321 USER "SYSTEM"/"MANAGER";//连接数据库TEST
	EXEC SQL DECLARE SX CURSOR FOR//定义游标SX
		SELECT Sno,Sname,Ssex,Sage //SX对应的语句
		FROM Student
		WHERE SDept=:department;
	EXEC SQL OPEN SX;//打开游标，指向查询结果的第一行
	for(;;)
		EXEC SQL FETCH SX INTO:HSno;HSname;HSsex;HSage;//推进游标，将当前数据放入主变量 
	if(SQLCA.SQLCODE!=0)//SQLCODE!=0 表示操作不成功 
		break;//利用SQLCA中的状态信息决定何时退出循环 
	if(count++==0)//如果是第一行的话，先打出行头 
		printf("\n%-10s%-20s-10s%-10s\n","Sno","Sname","Ssex","Sage");
	printf("%-10s%-20s%-10s%-10d\n",HSno,HSname,HSsex,HSage);//打印查询结果 
	printf("UPDATE AGE(Y/N)?");//询问用户是否要更新该学生的年龄 
	do{
		scanf("%c",&yn);
	}while(yn!='N'&&yn!='n'&&yn!='Y'&&yn!='y');
	if(yn=='y'||yn=='Y')//如果选择更新操作 
	{
		printf("INPUT NEW AGE:");
		scanf("%d",&NEWAGE);//用户输入新年龄到主变量中 
		EXEC SQL UPDATE Student SET Sage=:NEWAGE WHERE CURRENT OF SEX;//对当前游标指向的学生年龄进行更新	
	}
	EXEC SQL CLOSE SX;//关闭游标SX，不再和查询结果对应 
	EXEC SQL COMMIT WORK;//提交更新 
	EXEC SQL DISCONNECT TEST;//断开数据库连接 
		
}