Question

我收到此错误：

无效的对象名称＆＃39;会员＆＃39;

在这一行：

int MemberExist = (int)check_Member.ExecuteScalar();

使用我当前的DB，如下所示：http://imgur.com/6fyKGn3为什么不执行此操作？

代码：

// Get the connection 
SqlConnection DBConnection = new SqlConnection(@"Data Source=(LocalDB)\v11.0;AttachDbFilename=""E:\DS\Prac5\Part1\App_Data\MyDatabase.mdf"";Integrated Security=True");

SqlDataReader Reader = null;

DBConnection.Open();
SqlCommand check_Member = new SqlCommand("SELECT * FROM Members WHERE MembershipID = FirstName AND LastName = @Txtnput", DBConnection);
check_Member.Parameters.AddWithValue("@Txtnput", txtMembershipid.Text);

int MemberExist = (int)check_Member.ExecuteScalar();

Answer 1

您的连接字符串中似乎有一些错误。

Data Source=(LocalDb)\v11.0;Initial Catalog=Database;Integrated Security=SSPI;AttachDBFilename='E:\DS\Prac5\Part1\App_Data\MyDatabase.mdf'

您也可以使用

"SELECT TOP 1 MembershipID  FROM Members WHERE MembershipID = FirstName AND LastName = @Txtnput"

确保您的表名是成员。您可以在模型或数据库中检查它。

bool IsMemberExist;
object MembershipId = check_Member.ExecuteScalar();

if(MembershipId  != null )
 {
   IsMemberExist = true;
  //Do other things here.  //Convert.ToInt32(MembershipId) 
 }

Answer 2

请确保数据库MyDatabase.mdf是否包含名为Members的表。请测试以下。

SqlCommand check_table= "select case when exists((select * from information_schema.tables where table_name = '" + tableName + "')) then 1 else 0 end");
int IsTableExists = (int)check_table.ExecuteScalar();
if(IsTableExists ==1)
{
        SqlCommand check_Member = new SqlCommand("SELECT * FROM Members WHERE MembershipID = FirstName AND LastName = @Txtnput", DBConnection);
        check_Member.Parameters.AddWithValue("@Txtnput", txtMembershipid.Text);
        int MemberExist = (int)check_Member.ExecuteScalar();
}

更新：可以请用模式名称和表名更新查询。

例如：SqlCommand check_Member = new SqlCommand("SELECT * FROM dbo.Members WHERE MembershipID = FirstName AND LastName = @Txtnput", DBConnection);

或更具体地说是MyDatabase.dbo.Members

Answer 3

看起来您必须将查询更改为

"SELECT count(*) FROM Members WHERE MembershipID = FirstName AND LastName = @Txtnput"

因为ExecutesScalar需要从查询返回单个值。

Answer 4

尝试此连接字符串并检查

    SqlConnection DBConnection = new SqlConnection(@"Data Source=(LocalDB)\v11.0;
AttachDbFilename=E:\DS\Prac5\Part1\App_Data\Database.mdf;Integrated Security=True")

删除“之间没有必要，因为以@开头也将MyDatabase.mdf更改为Database.mdf，因为在图片中它是Database.mdf

SQL Server数据库中的对象名称无效？

4 个答案: