Differences

This shows you the differences between two versions of the page.

--- pracro:database [2010/06/03 16:33] – deva
+++ pracro:database [2010/06/07 11:17] (current) – deva
@@ Line 8: / Line 8: @@
 The first SQL command issued is BEGIN;
 If a 'commit' is received by the pracro server, it is translated into a COMMIT; on the SQL connection and the command string is cleared.
-If the clienbt disconnects without any actions, an ROLLBACK; is sent to the SQL server.
+If the client disconnects without any actions, an ROLLBACK; is sent to the SQL server.
 On reconnect to the session, the entire command string is replayed as it is, and the session is ready to continue where it left off.
-On the pracro 'discard' command, a ROLLBACK; is sent to the SQL server, and the command string is cleared.
+On the Pracro 'discard' command, a ROLLBACK; is sent to the SQL server, and the command string is cleared.
-====Sequence numbers====
+=====Journal uptodateness check=====
-All sequence numbers must be obtained from a seperate SQL conenction, that is not affected by the SQL transactions. It is vital that these numbers are not reused in later sessions.
+  * Person A is working on a patient P.
-All sequence numbers used in the pracro sessions must therefor be used as strings, directly in the syntax strings.
+  * Person A commits the macro M, with data "data from A".
+  * Person A 'close no commit'.
+  * Person B starts working on patient P.
+  * Person B commits the macro M, with data "data from B".
+  * Person B 'close and commit'.
+  * Person A continues work on patient P.
+  * Person A sees the resume of M being "data from B", and acknowledges it.
+  * Person A 'close and commit'
+Person A now **thinks** that the journal contains "data from B". But in fact it contains
 <code>
-global Db1
+data from B
-getSeq()
+data from A
-{
-  Mutex.lock
-  s = Db1.exec("currval('trseq')");
-  Mutex.unlock
-  return s;
-}
-do_something
-{
-   Db2
-   Db2.exec("BEGIN");
-   Db2.exec("INSERT INTO fields VALUES('foo', 'bar','"+getSeq()+"')");
-}
 </code>
+This is due to two problems: The field shown on the active session is not nesecarily the one being commit, when the entire session is committed. Second person A cannot see what changes has been made by others.