Question

我有一个名为“tbltrackuser”的表格，下面是“

Trackid (pk,identity)
Drafiid (bigint)
Userid (bigint)
Date (time)

我喜欢在第一次使用此表中的linq为特定用户和draftid插入记录，并且自动不在表中插入2次或更多次。

Trackid     draftid     userid      date
 1              20      user1       01-jan-13
 2              30      user1       02-jan-13
 4              20      user2       01-jan-13

例如系统自动未插入draftid = 20的记录下方，user = user1 at 03-jan-13 因为已经在01-jan-13之前插入了

  Trackid       draftid     userid      date
    3       20      user1       03-jan-13 (not inserted automatically)

Answer 1

您需要检查是否存在具有相同TrackID，草稿ID和用户ID

的记录

tbltrackuser trackuser = new tbltrackuser();
trackuser.TrackID = 1;
trackuser.DraftID  = 20;
trackuser.UserID = "user1";
trackuser.Date = "01-jan-13";

DataClasses1DataContext dc = new DataClasses1DataContext();

var sameRecords = from tu in dc.tbltrackusers
             where tu.DraftID == trackuser.DraftID
             && tu.UserID == trackuser.UserID
             && tu.Date == trackuser.Date
             select tu;

if (sameRecords.Count() == 0) //if there is no same record then you can insert
{
    dc.tbltrackusers.InsertOnSubmit(trackuser);
    dc.SubmitChanges();
}
else
    MessageBox.Show("Such record already exists.");

首次使用linq插入记录

1 个答案: