Question

我试图一次将一些数据插入到2个表中但是我的代码问题是......我一次只能插入一个表。如果我注释掉第一个插入语句，那么第二个插入将起作用，反之亦然。

这是我的代码

 SqlCommand cmd = new SqlCommand("select Name from MainTable where Name= '" + Name+ "'  ", sqlcon);
 SqlDataReader dr = cmd.ExecuteReader();
 if (dr.Read())
 {
    lblmsg.Text = "We are already have  this Name" + Name;
 }

 else
 {
    dr.Close();
    sqlcmd.CommandText = "INSERT INTO Table1(Name, Address) VALUES(@Name, @Address)";
    sqlcmd.CommandText = "INSERT INTO Table2(Company, Address2) VALUES(@Company, @Address2)";

    sqlcmd.Parameters.Clear();
    sqlcmd.Parameters.Add("@Name", SqlDbType.VarChar).Value = Name;
    sqlcmd.Parameters.Add("@Address", SqlDbType.VarChar).Value = Address;
    sqlcmd.Parameters.Add("@Company", SqlDbType.VarChar).Value = Company
    sqlcmd.Parameters.Add("@Address2", SqlDbType.VarChar).Value = Address2;

    sqlcmd.Connection = sqlcon;
    sqlcmd.ExecuteNonQuery();

    DV_NameAdd.ChangeMode(DetailsViewMode.ReadOnly);
    sqlcon.Close();
 }
 sqlcon.Close();

Answer 1

您正在覆盖原始的SqlCommand，这就是为什么一次只能运行一个。 SqlCommand一次只运行一个命令。它不接受您的代码似乎期望的其他版本的CommandText。如果要同时运行两个或更多命令，则必须创建一个以分号分隔的CommandText，如下所示：

sqlcmd.CommandText = 
"INSERT INTO Table1(Name, Address) VALUES(@Name, @Address);" + 
"INSERT INTO Table2(Company, Address2) VALUES(@Company, @Address2)";

注意两个命令之间的分号（;）。您的参数名称是唯一的，因此您应该没问题。

Answer 2

您正在设置相同SqlCommand的命令文本

  sqlcmd.CommandText = "INSERT INTO Table1(Name, Address) VALUES(@Name, @Address)";
  sqlcmd.CommandText = "INSERT INTO Table2(Company, Address2) VALUES(@Company, @Address2)";

只有最后一个将被执行，因为它已经替换了第一个。您可能需要执行第一个，清除参数集合，设置新文本然后重新执行，或创建单独的命令

  sqlcmd.CommandText = "INSERT INTO Table1(Name, Address) VALUES(@Name, @Address)";
  sqlcmd.Parameters.Add("@Name", SqlDbType.VarChar).Value = Name;
  sqlcmd.Parameters.Add("@Address", SqlDbType.VarChar).Value = Address;
  sqlCmd.ExecuteNonQuery();
  sqlCmd.Parameters.Clear();
  sqlcmd.CommandText = "INSERT INTO Table2(Company, Address2) VALUES(@Company, @Address2)";
  sqlcmd.Parameters.Add("@Company", SqlDbType.VarChar).Value = Company
  sqlcmd.Parameters.Add("@Address2", SqlDbType.VarChar).Value = Address2;
  sqlCmd.ExecuteNonQuery();

顺便说一句，第一个SELECT非常危险。您还应该为该命令使用参数

Answer 3

有时，您可以在两个SQL语句之间使用分号来一次执行两个。看看是否改变了这个：

sqlcmd.CommandText = "INSERT INTO Table1(Name, Address) VALUES(@Name, @Address)";
                    sqlcmd.CommandText = "INSERT INTO Table2(Company, Address2) VALUES(@Company, @Address2)";

到此：

sqlcmd.CommandText = "INSERT INTO Table1(Name, Address) VALUES(@Name, @Address);" +
"INSERT INTO Table2(Company, Address2) VALUES(@Company, @Address2)";

适合你。

Answer 4

要考虑的另一件事是将逻辑推入insert查询并消除竞争条件，如下所示：

public bool InsertEntry( string name , string addr1 , string company , string addr2 )
{
  const string QUERY = @"
begin transaction
declare @success bit

insert dbo.table_1
select @name , @addr1
where not exists ( select *
                   from dbo.main_table
                   where name = @name
                 )

insert dbo.table_2
select @company , @addr2
where @@rowcount = 1
  and not exists ( select *
                   from dbo.main_table
                   where name = @name
                 )
set @success = case when @@ROWCOUNT > 0 then 1 else 0 end

if ( @success = 1 )
begin
  commit transaction
end
else
begin
  rollback transaction
end

select @success
" ;
  bool success = false ;
  using ( SqlConnection connection = new SqlConnection( "Server=(local);Database=sandbox;Trusted_Connection=True;"))
  using ( SqlCommand command = connection.CreateCommand())
  {
    command.CommandType = CommandType.Text;
    command.CommandText = QUERY ;

    command.Parameters.Add( "@name"    , SqlDbType.VarChar ).Value = name    ;
    command.Parameters.Add( "@addr1"   , SqlDbType.VarChar ).Value = addr1   ;
    command.Parameters.Add( "@company" , SqlDbType.VarChar ).Value = company ;
    command.Parameters.Add( "@addr2"   , SqlDbType.VarChar ).Value = addr2   ;

    object returnedValue = command.ExecuteScalar() ;
    if ( returnedValue is bool )
    {
      success = (bool) returnedValue ;
    }
  }
  return success ;
}

使用C＃将一些数据插入多个表

4 个答案: