[Cl-perec-devel] Schema evolution problem

[Leslie P. Polzer]

Consider the following, questions as comments in-line:

PRC(7): *db1*
#<POSTGRESQL-POSTMODERN {B026989}>

PRC(8): (defpclass bar nil nil)
#<PERSISTENT-CLASS BAR>

PRC(9): (let ((*database* *db1*)) (with-transaction (defparameter bar (make-instance
'bar))))
BAR

PRC(10): (let ((*database* *db1*)) (with-transaction (describe bar)))
#<BAR :persistent #t 30 {B68B411}>
is an instance of class #<PERSISTENT-CLASS BAR>.
The following slots have :INSTANCE allocation:
 OID                  1986950
 PERSISTENT           T
 TRANSACTION          NIL
 TRANSACTION-EVENT    :CREATED

;; I didn't use REVIVE-/LOAD-INSTANCE here, but no error is signaled.
;; Why?

PRC(12): (defpclass* bar nil ((s :type (or unbound text))))
#<PERSISTENT-CLASS BAR>

PRC(13): (let ((*database* *db1*)) (with-transaction (describe bar)))
#<BAR :persistent #t 30 {B68B411}>
is an instance of class #<PERSISTENT-CLASS BAR>.
The following slots have :INSTANCE allocation:
 OID                  1986950
 PERSISTENT           T
 TRANSACTION          NIL
 TRANSACTION-EVENT    :CREATED
debugger invoked on a SIMPLE-ERROR in thread #<THREAD "initial thread" RUNNING {A698799}>:
  Accessing a persistent #<BAR :persistent #t 30 {B68B411}> while it is not attached to
the current transaction.

;; here an error *is* signaled...
;; continuing...

PRC(14): (let ((*database* *db1*)) (with-transaction (describe (revive-instance bar))))
debugger invoked on a CL-POSTGRES-ERROR:SYNTAX-ERROR-OR-ACCESS-VIOLATION in thread
#<THREAD "initial thread" RUNNING {A698799}>:
  Database error 42703: column "_s" does not exist
Query: SELECT _s FROM _bar WHERE (_oid = $1::BIGINT)

;; now that's the real issue: why hasn't the column for slot S been created?

  Leslie