在以下情況下使用靜態方法訪問數據庫安全嗎

Question

我正在將asp網站升級到asp.net。我正在嘗試遵循多種方法。 我的基本dal層如下，它返回一個數據表並插入給定的查詢。

using System; 
using System.Configuration; 
using System.Data; 
using MySql.Data.MySqlClient; 

public class mydatautility 
{ 
    public mydatautility() 
    { 
    } 
    public static DataTable Table(string query) 
    { 
     string constr = ConfigurationManager.ConnectionStrings["db_con"].ConnectionString; 
     DataTable table = new DataTable(); 
     try 
     { 
      using (MySqlConnection con = new MySqlConnection(constr)) 
      { 
       con.Close(); 
       MySqlCommand com = new MySqlCommand(query, con); 
       MySqlDataAdapter da = new MySqlDataAdapter(com); 
       con.Open(); 
       da.Fill(table); 
       con.Close(); 
       da = null; 
       com = null; 
       con.Dispose(); 
      } 
     } 
     catch (Exception) 
     { 
     } 
     return table; 
    } 
    public static int Insert_intoemployee(string query) 
    { 
     string constr = ConfigurationManager.ConnectionStrings["db_con"].ConnectionString; 
     int done = 0; 
     try 
     { 
      using (MySqlConnection con = new MySqlConnection(constr)) 
      { 
       MySqlCommand com = new MySqlCommand(query, con); 
       con.Open(); 
       done = com.ExecuteNonQuery(); 
       con.Close(); 
       com = null; 
       con.Dispose(); 
      } 
     } 
     catch (Exception) 
     { 
     } 
     return done; 
    } 
} 

我不確定當運行2個併發查詢時會發生什麼。
如何測試併發問題？

Answer 1

不會有併發問題，因爲每個請求都有自己的線程和靜態方法有單獨的調用每個線程的堆棧。但是，代碼中有一些建議。

using System; 
using System.Configuration; 
using System.Data; 
using MySql.Data.MySqlClient; 

public static class mydatautility//change to Utilities 
{ 
    public mydatautility()//not required in this scenario 
    { 
    } 
    public static DataTable Table(string query) //change method name to GetTable 
    { 
     string constr = ConfigurationManager.ConnectionStrings["db_con"].ConnectionString; 
     DataTable table = new DataTable(); 
     try 
     { 
      using (MySqlConnection con = new MySqlConnection(constr)) 
      { 
       con.Close();//not required 
       using(MySqlCommand com = new MySqlCommand(query, con)) 
       { 
       MySqlDataAdapter da = new MySqlDataAdapter(com); 
       con.Open(); 
       da.Fill(table); 
       con.Close(); 
       da = null;// reduntant, not required 
       com = null;// reduntant, not required 
       con.Dispose();// reduntant, not required 
       } 
      } 
     } 
     catch (Exception) 
     { 
     } 
     return table; 
    } 
    public static bool InsertEmployee(string query)// consider changing int to bool since you only require result of operation 
    { 
     string constr = ConfigurationManager.ConnectionStrings["db_con"].ConnectionString; 
     int done = 0; 
     try 
     { 
      using (MySqlConnection con = new MySqlConnection(constr)) 
      { 
       Using(MySqlCommand com = new MySqlCommand(query, con)) 
       { 
       con.Open(); 
       done = com.ExecuteNonQuery(); 
       con.Close(); 
       com = null;// reduntant, not required 
       con.Dispose();// reduntant, not required 
       } 
      } 
     } 
     catch (Exception) 
     { 
     } 
     return done > 0; // checks rows affected greater than 0 
    } 
} 

Answer 2

在這種情況下使用靜態方法是安全的。靜態方法中的變量與併發調用是隔離的！看到這個鏈接：variable in static methods inside static class

Answer 3

我認爲這是安全的，但不好的做法。如果您使用靜態方法訪問實時資源，那麼您想如何對它們進行單元測試？你不能真正模擬數據庫訪問。