SqlCommandcommand=newSqlCommand("SELECT * FROM users WHERE name = @name",connection);command.Parameters.AddWithValue("@name","John Doe"); 1.2. 使用正确的参数名称 确保在SQL查询中使用正确的参数名称。例如: 代码语言:csharp 复制 SqlCommandcommand=newSqlCommand("SELECT * FROM users WHERE name = @na...
(connectionString)) { SqlCommand command = new SqlCommand(query, connection); command.Parameters.AddWithValue("@Value1", value1); command.Parameters.AddWithValue("@Value2", value2); connection.Open(); int affectedRows = command.ExecuteNonQuery(); Console.WriteLine($"Number of rows affected: {...
SqlCommand command =newSqlCommand(commandText, connection); command.Parameters.Add("@ID", SqlDbType.Int); command.Parameters["@ID"].Value = customerID; //Use AddWithValue to assign Demographics. //SQL Server will implicitly convert strings into XML. command.Parameters.AddWithValue("@demographics",...
cmd.Parameters.AddWithValue("@id", DBNull.Value); else cmd.Parameters.AddWithValue("@id", str); cmd.Parameters[0].IsNullable =true;
(@Name, @Age)"Using cmd As New SqlCommand(sql, conn)'设置SqlCommand类对象的参数cmd.Parameters.AddWithValue("@Name", "David")cmd.Parameters.AddWithValue("@Age", 25)'执行SQL语句conn.Open()Dim count As Integer = cmd.ExecuteNonQuery()Console.WriteLine("{0} rows affected.", count)End UsingEnd...
1：必须和sql中的参数名一样，但加不加@都行。2：command.Parameters.Add("@ID", SqlDbType.Int);只是添加了个参数，但还没赋值。command.Parameters["@ID"].Value = customerID;这句是赋值，必须有。3：command.Parameters.AddWithValue("@demographics", demoXml);这句相当于上面两句合起来，你...
,connection)){command.Parameters.AddWithValue("@Username",username);command.Parameters.AddWithValue("@...
Integrated Security=True;" Using conn As New SqlConnection(connStr) Dim sql As String = "INSERT INTO myTable(Name, Age) VALUES(@Name, @Age)" Using cmd As New SqlCommand(sql, conn) '设置SqlCommand类对象的参数 cmd.Parameters.AddWithValue("@Name", "David") cmd.Parameters.AddWithValue("@Age...
command.Parameters.AddWithValue("@demographics", demoXml); try { connection.Open(); Int32 rowsAffected = command.ExecuteNonQuery(); Console.WriteLine("RowsAffected: {0}", rowsAffected); } catch (Exception ex) { Console.WriteLine(ex.Message); } } } 注解 Microsoft .NET Framework Data Provider...
command.Parameters.Add(parameter1);效率高于 command.Parameters.AddWithValue("@demographics", demoXml);。但是前者要通过SqlParameter parameter1 = new SqlParameter("@demographics", System.Data.SqlDbType.NChar, 10);指定好参数的类型。所以最好使用Add而不是AddWithValue。 4. SqlParameter要不要指定Size参数 分...