添加项目文件。

Epost.DAL/DB_Oracle.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Collections.Generic;
+using System.Configuration;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Epost.DAL
+{
+    public class DB_Oracle
+    {
+        private DataBaseOpration.OprationOraDAL db;
+        private string _strOracleMIDConnString = ConfigurationManager.ConnectionStrings["OraMidConnString"].ConnectionString;
+
+        public DB_Oracle()
+        {
+
+        }
+
+        /// <summary>
+
+        /// 此方法是本类实例的唯一全局访问点
+
+        /// （双重加锁 Double-Check Locking）
+
+        /// </summary>
+
+        /// <returns></returns>
+
+        public DataBaseOpration.OprationOraDAL GetInstance()
+        {
+
+            //如实例不存在，则New一个新实例，否则返回已有实例
+            if (db == null)
+            {
+
+                db = new DataBaseOpration.OprationOraDAL(_strOracleMIDConnString);
+
+            }
+            return db;
+
+
+        }
+
+
+
+
+    }
+}