EF C# 实例

最新推荐文章于 2022-08-31 17:47:10 发布

原创最新推荐文章于 2022-08-31 17:47:10 发布 · 391 阅读

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博客提及了四种常见的数据操作，分别是新增（New）、更新（Update）、删除（Delete）和查询（Select），这些操作在信息技术的数据处理中十分关键。

1: New

using (aipEntitiesSmartFeeder smartFeederEntities = new aipEntitiesSmartFeeder())
{
    setup_list _setupList = new setup_list();
    _setupList .mc_id = 1;
    _setupList.stage = 2;
    smartFeederEntities.setup_list.Add(_setupList);
    smartFeederEntities.SaveChanges();
}

2: Update

using (aipEntitiesSmartFeeder smartFeederEntities = new aipEntitiesSmartFeeder())
{
    setup_list _setupList = new setup_list();
    _setupList .mc_id = 1;
    _setupList.stage = 2;
    smartFeederEntities.Entry(_setupList).State = EntityState.Modified;
    smartFeederEntities.SaveChanges();
}

3:Delete

using (aipEntitiesSmartFeeder smartFeederEntities = new aipEntitiesSmartFeeder())
{
    setup_list _setupList = new setup_list();
    _setupList.mc_id = 1;
    _setupList.stage = 2;
    smartFeederEntities.Attach(_setupList);
    smartFeederEntities.Remove(_setupList);
    smartFeederEntities.SaveChanges();
}

4:Select

using (aipEntitiesSmartFeeder smartFeederEntities = new aipEntitiesSmartFeeder())
{

    var expr = from p in smartFeederEntities._setupList
                select p;
    foreach (var item in expr)
    {
        Console.WriteLine("{0}-{1}-{2}", item.mc_id , item.ProvinceNo, item.stage );
    }
}


using (aipEntitiesSmartFeeder smartFeederEntities = new aipEntitiesSmartFeeder())
{
    //根据TSQL查询
    DbSqlQuery<setup_list> dbSqlQuery = smartFeederEntities.setup_list.SqlQuery("select * from [setup_list] where [ID] = {0}", 2);

}