Using Split()

Dim connectionString As String = "Persist Security Info=False;Integrated Security=FALSE;database=DBNAME;server=111.111.11.11;user id=sa;pwd=beta;"

Dim splitComponents() As String = connectionString.Split(";")

For Each item As String In splitComponents
Dim splitAgain() As String = item.Split("=")
Dim left As String = splitAgain(0)
Dim right As String = splitAgain(1)
If left = "database" Then
sMainDB = right
Exit For
End If
Next