Linq to SQL 读取数据

Posted 2023-03-01 wuyb_2004

如下为通过Linq 读取SQL数据库数据的3种编码方法：

方式1：根据条件查询数据列表

DataContext dd = new DataContext(System.Configuration.ConfigurationManager.ConnectionStrings[configName].ConnectionString);

 Table<ADItem> tbl = dd.GetTable<ADItem>();

 Var query = tbl.Where(p => p.AC_ID == ac_id).ToList();

 

方式2：根据条件查询单个对象

Table<ADPublish> tbl =dd.GetTable<ADPublish>();

ADPublish adPublish = (from pin tbl where p.AP_ID == ap_idselect p).Single();

               

方式3：执行SQL查询数据列表

 string sql = string.Format(@"SELECT ADPublishUser.AP_ID,ADPublishUser.UserID,IoT_Meter.MeterNo FROM ADPublishUser ,IoT_Meter

WHEREADPublishUser.UserID = IoT_Meter.UserID and ADPublishUser.CompanyID =IoT_Meter.CompanyID and ADPublishUser.AP_ID =0", ap_id);

object[] param = new object[0];

 var query = dd.ExecuteQuery<ADPublisMeter>(sql,param).ToList();