Insert data into SQL Server from C# code

Question

I have a table student (id, name). Then I have one textbox, for entering the name, when click on submit button, it inserts the data into the databa

Answer 1

INSERT INTO student (name) values ('name')

Omit the id column altogether, it will be populated automatically. To use your variable, you should parameterise your SQL query.

string sql = "INSERT INTO student (name) values (@name)";
conn.Open();
SqlCommand cmd = new SqlCommand(sql, conn);
cmd.Parameters.Add("@name", SqlDbType.VarChar);
cmd.Parameters["@name"].Value = test;
cmd.ExecuteNonQuery();

You should never attempt to do this by constructing a SQL string containing the input value, as this can expose your code to SQL injection vulnerabilities.