Should I Use TableAdapters Or DataAdapters For My DAL?

So I just created a very nice dataset class with 30+ tables and relationships for a very large project. Each table has 3-8 associated queries besides the usual Fill/Get and then there will be many more in the BLL that utilize this DAL.  I then created a BaseDAL class and other DAL classes that inherit from the BaseDAL(has basic sql query access if needed).  What I want to know is if the way I am doing this is correct and if this is a good idea for a database of this size.  I've never used TableAdapters before and I don't know if I should be using them at all?  I don't know how they handle connections and if one user will have more than one connection open because of using them or will they all share an open connection? 

 Can someone please direct me.  Thank you! Also, if you notice in the top of the UserDAL code I have listed below, I declare and initialize the usersTableAdapter and usersDeptTableAdapter.  Should the call to create the object be moved into each function?Public Class Users : Inherits BaseDAL

Private usersDS As OEE_USERSTableAdapter = New OEE_USERSTableAdapter()Private usersDeptDS As OEE_USER_DEPTSTableAdapter = New OEE_USER_DEPTSTableAdapter()Private retcode As Integer = 0

 

#Region "USER"

' Returns employee ID if user is in system, otherwise returns 0

Public Function ValidateUser(ByVal username As String) As String

'Dim usersDS As OEE_USERSTableAdapter = New OEE_USERSTableAdapter()Dim dtUser As New OEE_USERSDataTable

dtUser = usersDS.GetUser(username)

If dtUser.Rows.Count = 1 ThenReturn dtUser.Rows(0)("EMPLID").ToString

Else

Return "0"

End IfEnd Function

 

'Add User

Public Function InsertUser(ByVal emplid As String, ByVal username As String) As String

Dim insertedEmplid As String = ""

emplid = usersDS.AddUser(emplid, username)Return insertedEmplid

End Function

Public Function FlagAsInactive(ByVal emplid As String) As Boolean

retcode = usersDS.FlagAsInactive(emplid)Return retcode <> 0

End Function

'Sets inactive flag to null for user (Reactivates them)

Public Function ActivateUser(ByVal emplid As String) As Boolean

retcode = usersDS.ActivateUser(emplid)

Return True

End Function

'Returns list of all usersPublic Function GetUsers() As DataTable

Return usersDS.GetUsers

End Function

#End Region