如何用多個表填充數據集？

Question

我想填充包含兩個表的一對多關係的數據集。 我使用的DataReader實現這一目標：

public DataSet SelectOne(int id) 
    { 
     DataSet result = new DataSet(); 
     using (DbCommand command = Connection.CreateCommand()) 
     { 
      command.CommandText = "select * from table1"; 

      var param = ParametersBuilder.CreateByKey(command, "ID", id, null); 
      command.Parameters.Add(param); 

      Connection.Open(); 
      using (DbDataReader reader = command.ExecuteReader()) 
      { 
       result.MainTable.Load(reader); 
      } 
      Connection.Close(); 
     } 
     return result; 
    } 

但我有隻有一個表填滿。我如何實現我的目標 - 填寫兩張表格？

我想用DataReader代替DataAdapter，如果可能的話。

Answer 1

如果您發出帶有多個SELECT語句一條命令，你可以使用NextResult方法來DataReader的範圍內移動到下一個結果集：http://msdn.microsoft.com/en-us/library/system.data.idatareader.nextresult.aspx

我展示它可能看起來波紋管：

public DataSet SelectOne(int id) 
{ 
    DataSet result = new DataSet(); 
    using (DbCommand command = Connection.CreateCommand()) 
    { 
     command.CommandText = @" 
select * from table1 
select * from table2 
     "; 

     var param = ParametersBuilder.CreateByKey(command, "ID", id, null); 
     command.Parameters.Add(param); 

     Connection.Open(); 
     using (DbDataReader reader = command.ExecuteReader()) 
     { 
      result.MainTable.Load(reader); 
      reader.NextResult(); 
      result.SecondTable.Load(reader); 
      // ... 
     } 
     Connection.Close(); 
    } 
    return result; 
} 

Answer 2

Here is very good answer of your question

見上文MSDN頁面提及的示例： -

Answer 3

填充數據集無線可以通過向數據庫發送多個請求或以更快的方式完成多個表：可以通過單個請求將多個SELECT語句發送到數據庫服務器。這裏的問題是從查詢生成的表具有自動名稱Table和Table1。但是，生成的表名可以映射到應在DataSet中使用的名稱。

SqlDataAdapter adapter = new SqlDataAdapter(
     "SELECT * FROM Customers; SELECT * FROM Orders", connection); 
adapter.TableMappings.Add("Table", "Customer"); 
adapter.TableMappings.Add("Table1", "Order"); 

adapter.Fill(ds); 

Answer 4

這是一個老話題，但對於一些人來說可能是有用的：

 DataSet someDataSet = new DataSet(); 
     SqlDataAdapter adapt = new SqlDataAdapter(); 

     using(SqlConnection connection = new SqlConnection(ConnString)) 
     { 
      connection.Open(); 
      SqlCommand comm1 = new SqlCommand("SELECT * FROM whateverTable", connection); 
      SqlCommand comm2g = new SqlCommand("SELECT * FROM whateverTable WHERE condition = @0", connection); 
      commProcessing.Parameters.AddWithValue("@0", "value"); 
      someDataSet.Tables.Add("Table1"); 
      someDataSet.Tables.Add("Table2"); 

      adapt.SelectCommand = comm1; 
      adapt.Fill(someDataSet.Tables["Table1"]); 
      adapt.SelectCommand = comm2; 
      adapt.Fill(someDataSet.Tables["Table2"]); 
     } 

Answer 5

protected void Page_Load(object sender, EventArgs e) 
{ 
    SqlConnection con = new SqlConnection("data source=.;uid=sa;pwd=123;database=shop"); 
    //SqlCommand cmd = new SqlCommand("select * from tblemployees", con); 
    //SqlCommand cmd1 = new SqlCommand("select * from tblproducts", con); 
    //SqlDataAdapter da = new SqlDataAdapter(); 

    //DataSet ds = new DataSet(); 
    //ds.Tables.Add("emp"); 
    //ds.Tables.Add("products"); 
    //da.SelectCommand = cmd; 
    //da.Fill(ds.Tables["emp"]); 
    //da.SelectCommand = cmd1; 

    //da.Fill(ds.Tables["products"]); 
    SqlDataAdapter da = new SqlDataAdapter("select * from tblemployees", con); 
    DataSet ds = new DataSet(); 
    da.Fill(ds, "em"); 
    da = new SqlDataAdapter("select * from tblproducts", con); 
    da.Fill(ds, "prod"); 

    GridView1.DataSource = ds.Tables["em"]; 
    GridView1.DataBind(); 
    GridView2.DataSource = ds.Tables["prod"]; 
    GridView2.DataBind(); 
}