利用LINQ to SQL 增删改查本地数据库

1. LINQ to SQL查询数据库

   //查询数据库
   using (DbAppDataContext context = new DbAppDataContext())
   {
          context.Log = Console.Out;
          var query = from p in context.PeopleInfoTables
                      let length = p.Names.Length
                      orderby length
                      select new { Name = p.Names, Length = length };
          foreach (var entry in query)
          {
                Console.WriteLine("{0}:{1}", entry.Name, entry.Length);
          }
   }
   
   输出结果
   

2. LINQ to SQL增加数据库信息

   //往数据库增加信息
   using (DbAppDataContext context = new DbAppDataContext())
   {
        context.Log = Console.Out;
        context.PeopleInfoTables.InsertOnSubmit(new PeopleInfoTable
        {
            Names = "Qinan",
            Addresses = "Shaoxing",
            Ages = 24,
            ID = "1231231",
            Nations = "China",
            Phones = "18868875132"
         });
         context.SubmitChanges();
         var query = from p in context.PeopleInfoTables
             select new { Name = p.Names, Address = p.Addresses };
         foreach (var entry in query)
         {
             Console.WriteLine("{0}:{1}", entry.Name, entry.Address);
         }
   }
   
   输出结果
   

3. LINQ to SQL删除数据库信息

   //删除数据库某条信息
   using (DbAppDataContext context = new DbAppDataContext())
   {
         context.Log = Console.Out;
         var people = context.PeopleInfoTables.SingleOrDefault(p => p.Names == "Qinan");
         if (people != null)
         {
             context.PeopleInfoTables.DeleteOnSubmit(people);
             context.SubmitChanges();
         }
         var query = from p in context.PeopleInfoTables
              select new { Name = p.Names, Address = p.Addresses };
         foreach (var entry in query)
         {
              Console.WriteLine("{0}:{1}", entry.Name, entry.Address);
         }
   }
   
   输出结果

4. LINQ to SQL编辑数据库

   //编辑数据库中的信息
   using (DbAppDataContext context = new DbAppDataContext())
   {
       context.Log = Console.Out;
       var people = context.PeopleInfoTables.SingleOrDefault(p => p.Names == "Yuan");
       if (people != null)
       {
           people.Ages = 50;
           people.Addresses = "tanggu";
           context.SubmitChanges();
       }
       var query = from p in context.PeopleInfoTables
            select new {Name = p.Names, Age = p.Ages, Address = p.Addresses};
       foreach (var entry in query)
       {
            Console.WriteLine("{0}:{1},{2}", entry.Name, entry.Age, entry.Address);
       }
   }
   
   输出结果
   
   

    

利用LINQ to SQL 增删改查本地数据库

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