vb.net - SELECT UPDATE SQL Not Working -

i have 2 forms

first form has

public class frmmain  friend strbillidnumber string friend strbillpassword string friend ds new dataset friend cnn oledbconnection friend sql string friend adptr oledbdataadapter dim attempt integer = 1  private sub btnsign_click(sender object, e eventargs) handles btnsign.click      dim connectionstring string     connectionstring = "provider=microsoft.ace.oledb.12.0;data source=c:\users\renz\documents\visual studio 2012\final\database\usersdb.accdb;"     sql = "select id, lastname, firstname, loginstatus tbluser"     cnn = new oledbconnection(connectionstring)     try         cnn.open()         adptr = new oledbdataadapter(sql, cnn)         adptr.fill(ds)            = 0 ds.tables(0).rows.count - 1              if ds.tables(0).rows(i).item(0) = txtid.text                 messagebox.show("username matched")                 if ds.tables(0).rows(i).item(1) = txtpassword.text                     messagebox.show("password matched")                      if txtpassword.text = "admin"                         messagebox.show("you logged in admin.")                         frmfaculty.show()                         me.hide()                     else                         frmstudent.lblsi.text = ds.tables(0).rows(i).item(0)                         frmstudent.lblln.text = ds.tables(0).rows(i).item(1)                         frmstudent.lblfn.text = ds.tables(0).rows(i).item(2)                         frmstudent.lblls.text = ds.tables(0).rows(i).item(3)                         messagebox.show("you logged in.")                         frmstudent.show()                         me.hide()                     end if                 else                     messagebox.show("invalid password.")                     messagebox.show("please try again." & vbnewline & "attempt: " & attempt & " out of 3")                     attempt = attempt + 1                 end if             end if          next          adptr.dispose()         cnn.close()     catch ex exception         messagebox.show("please try again!")     end try      'log-in attempt 3x fail'     if attempt > 3         messagebox.show("you have exceeded number of login attempt." & vbnewline & "please contact administrator.")     end if end sub 

and second form has

imports system.data.oledb  public class frmstudent dim timeinhold string private sub loginbtn_click(sender object, e eventargs) handles loginbtn.click      dim cnn2 new oledbconnection     dim command oledbcommand     dim integer     dim sql2 string     dim status string      try         cnn2 = new oledbconnection("provider=microsoft.jet.oledb.4.0;data source=c:\users\renz\documents\visual studio 2012\final\database\auditdb.mdb;")         cnn2.open()          sql2 = "insert audit ([id],[timein]) values('" & frmmain.txtid.text & "','" & datetime.now & "')"          command = new oledbcommand(sql2, cnn2)         = command.executenonquery      catch ex exception         cnn2.close()      end try      messagebox.show("you have signed in." & vbnewline & " please don't forget logout.")     frmmain.cnn = new oledbconnection("provider=microsoft.ace.oledb.12.0;data source=c:\users\renz\documents\visual studio 2012\final\database\usersdb.accdb;")     frmmain.cnn.open()     frmmain.adptr = new oledbdataadapter(frmmain.sql, frmmain.cnn)     frmmain.adptr.fill(frmmain.ds)     if frmmain.ds.tables(0).rows(i).item(0) = lblsi.text         frmmain.sql = "update tbluser set loginstatus = 'signedin'"          frmmain.cnn.close()     end if     me.close()     frmmain.show()     frmmain.txtid.text = string.empty     frmmain.txtpassword.text = string.empty end sub 

i can't select , update sql statement work data set form 1. , when button clicked, update field "loginstatus" value of "signed in".

p.s. i'm creating time-in, time-out monitoring system determine if user admin or student , redirect them corresponding forms. student form have sign in , sign out buttons, , record time in , time out. when sign in clicked, grayed out.

please help..

i think missing executenonquery in second form , there 1 user query fine if more 1 consider using " clause" eg.

sql= "update tbluser set loginstatus = 'signedin' id =" <provide id> 

if doesn't solve problem feel free ask more.

regards.