ADO.NET獲取數據數據（DataSet）同時獲取表的架構

普通的ADO.NET獲取DataSet的寫法如下：

using System.Configuration;
using System.Data;
using System.Data.SqlClient;
public class SQLHelper
{
    private static readonly string ConnectionString = ConfigurationManager.ConnectionStrings["Default"].ConnectionString;

    public static DataSet GetDataSet(string sql)
    {
        using (SqlConnection conn =new SqlConnection(ConnectionString))
        {
            SqlCommand cmd = new SqlCommand(sql, conn);
            SqlDataAdapter adapter = new SqlDataAdapter(cmd);
            DataSet ds = new DataSet();
            conn.Open();
            adapter.Fill(ds);
            return ds;
        }
    }
}

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <connectionStrings>
    <add name="Default" connectionString="Data Source=.;Initial Catalog=EFDb;Integrated Security=true"/>
  </connectionStrings>
</configuration>

這裡需要獲取DataTable的主鍵信息，調試時發現沒有主鍵信息，而實際資料庫中是有主鍵（Id）

此時需要給SqlDataAdapter設置屬性MissingSchemaAction為System.Data.MissingSchemaAction.AddWithKey

修改後的SQLHelper為

using System.Configuration;
using System.Data;
using System.Data.SqlClient;
public class SQLHelper
{
    private static readonly string ConnectionString = ConfigurationManager.ConnectionStrings["Default"].ConnectionString;

    public static DataSet GetDataSet(string sql)
    {
        using (SqlConnection conn =new SqlConnection(ConnectionString))
        {
            SqlCommand cmd = new SqlCommand(sql, conn);
            SqlDataAdapter adapter = new SqlDataAdapter(cmd);
            adapter.MissingSchemaAction = MissingSchemaAction.AddWithKey;
            DataSet ds = new DataSet();
            conn.Open();
            adapter.Fill(ds);
            return ds;
        }
    }
}