We were discussing detecting accounts owned by a user and displaying last signed in. We referred only to the last signed in feature without descrption of its implementation. This information can be persisted as a single column in the identity table. Most tables generally have Created, Modified timestamps so in this case we can re-purpose the modified timestamp.  However the Identity record may also be modified for purposes other than last signed in. In addition, the last signed in activity is also more informational when it describes the device from which it is signed in. Therefore keeping track of devices table joined with login time will help this case.  Making an entry for the device id and timestamp is sufficient and we only need to keep track of one per login used by the owner. Translation to domain objects can then proceed with Object Relational Mapping. Finally we merely add an attribute on the view model for the display on the page.
The data is all read and write by the system and therefore has no special security considerations. It is merely for display purposes.

#codingexercise
Print all possible palindromic partitions of a string

We can thoroughly exhaust the search space by enumerating all substrings 
with starting position as 0 to Length-1 
and size of substring as that single character itself to a length including the last possible character.
For each of these substrings, we can determine whether it is a palindrome or not
bool isPalindrome(string A)
{
int start = 0; 
int end = A.Length-1;
bool ret = false;
if (A.Length == 0) return false;
while(start <= end)
{
if (A[start] != A[end])
{
return false;
}
start++;
end--;
}
ret = true;
return ret;
}