update after select doesn't update...

update after select doesn't update...

Am retrieveing an "available" ipaddress from a table, then later trying to
perform an update to "assign" the address to an id.  The update produces no
error, but doesn't update either.  Must be overlooking something but can't place
a finger on it.

    Table "host_ipaddress"
 Attribute |  Type   | Modifier
-----------+---------+----------
 server    | text    | not null
 type      | text    |
 hostnum   | integer | not null
 address   | text    |
Index: host_ipaddress_pkey