Question

我发现了这个错误。我该怎么解决这个问题？

这是我的创建查询

CREATE TABLE [dbo].[candidatedetails](
    [id] [int] IDENTITY(1,1) NOT NULL,
    [cname] [varchar](50) NULL,
    [pname] [varchar](50) NULL,
    [cno] [varchar](50) NULL,
    [pno] [varchar](50) NULL,
    [address] [varchar](max) NULL,
    [year] [varchar](50) NULL,
    [class] [varchar](50) NULL,
    [branch] [varchar](50) NULL,
    [totalfees] [numeric](18, 0) NULL,
    [paidfees] [numeric](18, 0) NULL,
    [pendingfees] [numeric](18, 0) NULL,
    [idno] [int] NULL,
 CONSTRAINT [PK_candidatedetails] PRIMARY KEY CLUSTERED 
(
    [id] ASC
)

这是代码

SqlConnection con = new SqlConnection(constring);
            con.Open();
            if(con.State==ConnectionState.Open)
            {
                string q = "INSERT INTO candidatedetails(id,cname,pname,cno,pno,address,year,class,branch,totalfees,paidfees,pendingfees,idno) VALUES ('','"+cname+"','"+pname+"','"+cno+"','"+pno+"','"+address+"','"+year+"','"+class1+"','"+branch+"','"+totalfees+"','"+paidfees+"','"+pendingfees+"','"+idno+"')";
                SqlCommand com = new SqlCommand(q, con);
                com.ExecuteNonQuery();
                MessageBox.Show("Candidate is registered");
            }

我在“com.executenonquery（）”

行上收到此错误

Answer 1

您的id列被声明为IDENTITY，因此它会在插入时自动生成一个值。您不必将其包含在插入列列表中，也不必为其提供值。

string q = "INSERT INTO candidatedetails(cname,pname,cno,pno,address,year,class,branch,totalfees,paidfees,pendingfees,idno) VALUES ('"+cname+"','"+pname+"','"+cno+"','"+pno+"','"+address+"','"+year+"','"+class1+"','"+branch+"','"+totalfees+"','"+paidfees+"','"+pendingfees+"','"+idno+"')";

另外，要注意像这样动态生成SQL，容易出错（例如，如果你的某个值有未转义的单引号）和 SQL注入如果值来自用户输入或其他不安全的来源。

您应该创建一个接收这些参数的存储过程，或者使用sp_executesql构建sql。

Answer 2

只需删除id表单sql查询：试试这个：

 SqlConnection con = new SqlConnection(constring);
                con.Open();
                if(con.State==ConnectionState.Open)
                {
                    string q = "INSERT INTO candidatedetails(cname,pname,cno,pno,address,year,class,branch,totalfees,paidfees,pendingfees,idno) VALUES ('"+cname+"','"+pname+"','"+cno+"','"+pno+"','"+address+"','"+year+"','"+class1+"','"+branch+"','"+totalfees+"','"+paidfees+"','"+pendingfees+"','"+idno+"')";
                    SqlCommand com = new SqlCommand(q, con);
                    com.ExecuteNonQuery();
                    MessageBox.Show("Candidate is registered");
                }

当IDENTITY_INSERT设置为OFF时，无法在表'candidatedetails'中为identity列插入显式值

2 个答案: