如何在SQL和C＃中只插入一个ID的五个值 [英] How to insert only five values a an ID in SQL and C#

问题描述

我想为每个学生添加五个主题标记...我将如何限制Stduent_ID？如果Stduent_ID = 1并且插入五次然后六个条目我不应该添加...我将如何在C＃中执行此操作+ SQL ...



我的尝试：



声明@Counter int

设置@ Counter =（SELECT Count（Student_ID）为'StudentCount'

来自CourseSemOne

其中Student_ID = 3 Group by Student_ID ）

if（@Counter> = 6）

print'Sorry！你不能为一个stduent添加超过五个主题数据'

其他

打印'插入查询'

解决方案

< blockquote> minor correction

  if （ @ Counter > =  5 ）

string sql = SELECT Count（Student_ID）FROM CourseSemOne，其中Student_ID ='" + Student_ID +"'Group by Student_ID" ;;

SqlConnection con = new SqlConnection（@Data Source = LOCALHOST \ SQLEXPRESS;初始目录= CS_DB;集成安全性=真）;

con.Open（）;

SqlCommand cmd = new SqlCommand（sql，con）;

int count = Convert.ToInt32（cmd.ExecuteScalar（））;

con.Close（）;



if （计数< 5&& count> = 0）

{

obj.insertSemCourseOne（Student_ID，Course_Code，Course_Title，Total_Marks，Obtain_Marks，Grade，Value，Cr_Hours，Grade_Point，GPA，CGPA）;

// DatabaseConnnectionClass.UserMessage（" Added"）;

MessageBox.Show（" Added Subject"）;

Dataloaddd（）;

}

其他

{



MessageBox.Show（&抱歉！对于这个学号=" + Student_ID +"您不能添加超过5个数据。）;

}

i want to add only five subject marks for each student...how i will restrict an Stduent_ID ?if Stduent_ID=1 and inserted five times then for six entry i should not add...how i will do it in C# + SQL...

What I have tried:

Declare @Counter int
Set @Counter=(SELECT Count(Student_ID) as 'StudentCount'
FROM CourseSemOne
where Student_ID=3 Group by Student_ID )
if(@Counter >= 6)
print'Sorry! You cannot add more than five subject data for a single stduent'
else
print 'Insert Query'

解决方案

minor correction

if(@Counter >= 5)

string sql = "SELECT Count(Student_ID) FROM CourseSemOne where Student_ID='"+Student_ID+"' Group by Student_ID ";
SqlConnection con = new SqlConnection(@"Data Source=LOCALHOST\SQLEXPRESS;Initial Catalog=CS_DB;Integrated Security=True");
con.Open();
SqlCommand cmd = new SqlCommand(sql, con);
int count = Convert.ToInt32(cmd.ExecuteScalar());
con.Close();

if (count <5 && count >=0)
{
obj.insertSemCourseOne(Student_ID, Course_Code, Course_Title, Total_Marks, Obtain_Marks, Grade, Value, Cr_Hours, Grade_Point, GPA, CGPA);
// DatabaseConnnectionClass.UserMessage("Added");
MessageBox.Show("Added Subject");
Dataloaddd();
}
else
{

MessageBox.Show("Sorry!For this Student ID = "+Student_ID+" You cannot add more than 5 data.");
}

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