[jrf-devel] PostgreSQL Timestamp Optimistic Locking...

[Mandip S. S. <ma...@su...>]

Hi All

Been working on getting all the tests to pass for PostgreSQL database 
and came up with an interesting issue...

If we create a Domain that uses timestamp optimistic locking then the 
timestamp string in the db will look like:
'2002-04-08 17:48:30.123456+01'

However when we retrieve a PersistentObject from the table and hence 
read the timestamp column value (using rs.getTimestamp(columnName)) the 
timestamp string is stored as '2002-04-08 17:48:30.123'.

If we now modify our PersistentObject and try to save it back to the db 
with a statement like:
UPDATE Domain f1=..., f2=..., f3=..., WHERE id=... AND 
timestampColumnName='2002-04-08 17:48:30.123'

Then the statement will obviously fail and we get an 
ObjectHasChangedException even though the row actually hasn't been 
updated since we last read from it.  So the issue here being how do we 
get round the problem of different timestamp representations in the db 
and within the framework?

To get round this problem I've changed the statement to:
UPDATE Domain f1=..., f2=..., f3=..., WHERE id=... AND 
timestampColumnName LIKE '2002-04-08 17:48:30.123%'

What do you guys think of the above change?  Are there any other 
suggestions?  Is this something we might have to put into the 
DatabasePolicy?

Regards
Mandip