System.Data.SqlClient.SqlException:无法打开数据库"；数据库”；登录时请求.登

我正在尝试访问sql数据库。我在VS2013 C#中创建。但我一直收到这个错误

'无法打开登录请求的数据库"database"。登录失败。'

我正在尝试使用IIS管理器在本地主机上运行此程序。我在web配置中的连接字符串是否指向错误的数据源？我可能把mdf和日志文件放错地方了？我创建了mdf和日志文件，并将它们放在appdata文件夹中。

       //objects we will need to work with the db
        SqlConnection conn;
        SqlCommand cmd;
        //IF PAGE IS NOT A POSTBACK, ADD A HIT
        if (!Page.IsPostBack)
        {
            //connect to the db
            //conn = new SqlConnection(@"Data Source");
            conn = new  
               SqlConnection(WebConfigurationManager.ConnectionStrings
               ["ConnectionString"].ConnectionString);
            //the sql command to increment hits by 1
            cmd = new SqlCommand("UPDATE Hits SET Hits = Hits+1 WHERE 
            Name=@Name", conn);
            cmd.CommandType = CommandType.Text;
            //update where Name is 'Default' which corresponds to this page
            cmd.Parameters.AddWithValue("@Name", "WebForm1");
            using (conn)
            {
                //open the connection
                conn.Open();
                //send the query
                cmd.ExecuteNonQuery();
            }
        }

        //DISPLAY HITS IN OUR LABEL
        //connect to the db
        conn = new SqlConnection(WebConfigurationManager.
                ConnectionStrings["ConnectionString"].
                 ConnectionString);
        //the sql command to select the row of hits corresponding to this           
        page
        cmd = new SqlCommand("SELECT * FROM Hits WHERE Name=@Name", conn);
        cmd.CommandType = CommandType.Text;
        //select where Name is 'Default' which corresponds to this page
        cmd.Parameters.AddWithValue("@Name", "WebForm1");
        using (conn)
        {
            //open the connection
            conn.Open();
            //send the query and store the results in a sqldatareader
            SqlDataReader rdr = cmd.ExecuteReader();
            if (rdr.Read())
            {
                //set the text of our label to the current # of hits
                lblHits.Text = "Default Page Hits - " +  
                rdr["Hits"].ToString();
            }
        }

web.config 中的连接字符串

<configuration>
   <system.web>
       <compilation debug="true" targetFramework="4.0" />
   </system.web>
  <connectionStrings>
     <add name="ConnectionString" connectionString="Data Source=            
     (local)'SQLEXPRESS; Initial Catalog=Database; Integrated Security=True" 
     providerName="System.Data.SqlClient"/>
  </connectionStrings>
</configuration>

Integrated Security=SSPI