ADO.NET获取数据（DataSet）同时获取表的架构

普通的ADO.NET获取DataSet的写法如下：

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>

这里需要获取DataTable的主键信息，调试时发现没有主键信息，而实际数据库中是有主键（Id）

此时需要给SqlDataAdapter设置属性MissingSchemaAction为System.Data.MissingSchemaAction.AddWithKey

修改后的SQLHelper为

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;
        }
    }
}