连接SQL数据库的2种方法 .NET-优快云博客

本文介绍了两种从SQL数据库中检索数据的方法：使用SqlCommand与SqlDataAdapter。通过具体的代码示例展示了如何建立连接、执行查询并显示结果。SqlCommand适用于简单查询，而SqlDataAdapter则更适合于需要填充数据集的场景。

第一种 SqlCommand

<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Data.SqlClient" %>
<script Language="c#" runat="server">
void Page_Load()
{
    string strConnection = "server=IPROMISE//SQLEXPRESS;database=Show5new;uid=sa;password=;";
    data_src.Text = strConnection;;
    SqlConnection objConnection = new SqlConnection(strConnection);
    try
    {
      objConnection.Open();
      SqlCommand objSqlCommand = new SqlCommand("SELECT Username,Password,QQ,LoginIP FROM Show5_ALLUser;",objConnection);
      myGrid.DataSource = objSqlCommand.ExecuteReader();
      myGrid.DataBind();
      con_open.Text="Connection opened successfully.<br />";
      objConnection.Close();
      con_close.Text="Connection closed.<br />";
    }
    catch (Exception e)
    {
      con_open.Text="Connection failed to open.<br />";
      con_close.Text=e.ToString();
    }
}
</script>
<html>
<body>
<h4>Testing the data connection
<asp:label id="data_src" runat="server"/></h4>
<asp:label id="con_open" runat="server"/><br />
<asp:label id="con_close" runat="server"/><br />
<asp:Label ID="mycc" runat="server" /><br />
<asp:DataGrid ID="myGrid" runat="server" />
</body>
</html>

底二种 SqlDataAdapter

<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Data.SqlClient" %>
<script Language="c#" runat="server">
void Page_Load()
{
      SqlCommand objSqlCommand = new SqlCommand("SELECT Username,Password,QQ,LoginIP FROM Show5_ALLUser;");
      string strSQL = "SELECT Username,Password,QQ,LoginIP FROM Show5_ALLUser;";
    string strConnection = "server=IPROMISE//SQLEXPRESS;database=Show5new;uid=sa;password=;";
    data_src.Text = strConnection;;
    DataSet objDataSet = new DataSet();
    SqlConnection objConnection = new SqlConnection(strConnection);
    try
    {
      objConnection.Open();
      SqlDataAdapter objDataAdapter = new SqlDataAdapter(strSQL, objConnection);
      objDataAdapter.Fill(objDataSet);
      myGrid.DataSource = objDataSet;
      myGrid.DataBind();
      con_open.Text="Connection opened successfully.<br />";
      objConnection.Close();
      con_close.Text="Connection closed.<br />";
    }
    catch (Exception e)
    {
      con_open.Text="Connection failed to open.<br />";
      con_close.Text=e.ToString();
    }
}
</script>
<html>
<body>
<h4>Testing the data connection
<asp:label id="data_src" runat="server"/></h4>
<asp:label id="con_open" runat="server"/><br />
<asp:label id="con_close" runat="server"/><br />
<asp:DataGrid ID="myGrid" runat="server" />
</body>
</html>