C # determine whether the values in a column field in the database table exist

1           //  Modify website file module  2           Public   Int Upstatewebproductscontentconfig ( Long Itestid, Int  Iseq)// Itestid is the ID of the website file, and iseq is the field value to be modified  3   {  4               If (_ Iloginret! = 0 )Return - 1  ;  5   6 STC. model. showwebproductscontentconfig mshowwebproductscontentconfig = New  Model. showwebproductscontentconfig ();  7 Duser. stablename = Mshowwebproductscontentconfig. stablename;  8               String Strsql = "  Iseq = " + Iseq. tostring () + "   "  ;// As a condition for Searching databases  9               Int Flag = Duser. getcount (strsql );// Use the getcount common function to search for the iseq field = number of values in the database. If there are multiple iseq fields, you cannot set them again.  10               If (Flag> 0  )// If flag = 0,-4 is returned, and Ajax prompts an error at the front-end  11                   Return - 4  ;  12   Duser. GetModel (mshowwebproductscontentconfig, itestid );//GetModel is a parent function and a public method. When it is modified, the values of other fields are not affected.  13               If (Mshowwebproductscontentconfig = Null ) Return - 3  ;  14   15 Mshowwebproductscontentconfig. iseq =Iseq;// If there are no duplicatesModify the value of this field  16   Duser. Update (mshowwebproductscontentconfig );// This is a parent function for modification.  17   18               Return   0  ;  19 }