Développement sous MySQL et langage Ada : Comment implémenter les fonctions de calcul de données

with SQL;
with Ada.Text_IO;

procedure MySQL_Connect is
   package SQL_IO is new Ada.Text_IO.Text_IO (File => SQL);
   
   -- 创建连接
   DB_Connection : SQL.Connection;
   Error_Message : SQL_IO.File_Type;

   -- 数据库连接信息
   Username : constant String := "your_username";
   Password : constant String := "your_password";
   Database : constant String := "your_database";
begin
   -- 连接到数据库
   SQL.Connect (DB_Connection, Username, Password, Database, Error_Message);
   
   -- 检查连接是否成功
   if DB_Connection.Is_Connected then
      SQL_IO.Put_Line ("连接成功!");
   else
      SQL_IO.Put_Line ("连接失败: " & Error_Message.all);
   end if;
   
   -- 关闭连接
   SQL.Disconnect (DB_Connection);
end MySQL_Connect;

with SQL;
with Ada.Text_IO;

procedure Data_Calculation is
   package SQL_IO is new Ada.Text_IO.Text_IO (File => SQL);
   
   -- 创建连接
   DB_Connection : SQL.Connection;
   Error_Message : SQL_IO.File_Type;

   -- 数据库连接信息
   Username : constant String := "your_username";
   Password : constant String := "your_password";
   Database : constant String := "your_database";
   
   -- SQL查询语句
   Query : constant String :=
      "SELECT SUM(column_name) FROM table_name;";
   
   -- 查询结果
   Sum_Value : Integer;
begin
   -- 连接到数据库
   SQL.Connect (DB_Connection, Username, Password, Database, Error_Message);
   
   -- 检查连接是否成功
   if DB_Connection.Is_Connected then
      SQL_IO.Put_Line ("连接成功!");
   else
      SQL_IO.Put_Line ("连接失败: " & Error_Message.all);
      return;
   end if;
   
   -- 执行查询
   declare
      Result_Set : SQL.Result_Set;
   begin
      SQL.Execute (Result_Set, DB_Connection, Query, Error_Message);
      
      -- 获取查询结果
      SQL_IO.Get_Column (Result_Set, 1, Sum_Value);
      
      -- 输出查询结果
      SQL_IO.Put_Line ("总和: " & Sum_Value'Image);
      
      -- 关闭结果集
      SQL.Close (Result_Set);
   exception
      when others =>
         SQL_IO.Put_Line ("查询失败: " & Error_Message.all);
   end;
   
   -- 关闭连接
   SQL.Disconnect (DB_Connection);
end Data_Calculation;