On Jun 18, 2007, at 3:34 PM, Christoph Haas wrote:
> assign_mapper(session_context, DhcpHost, dhcp_hosts_table)
>
> assign_mapper(session_context, DnsRecord, powerdns_records_table,
> properties={
> 'dhcphost': relation(DhcpHost,
> primaryjoin=(cast
> (powerdns_records_table.c.content,PGInet)
> ==dhcp_hosts_table.c.ip_address),
> foreign_keys=[powerdns_records_table.c.content]),
> }
> )
>
also, this works:
mapper(DhcpHost, dhcp_hosts_table)
mapper(DnsRecord, powerdns_records_table,
properties={
'dhcphost': relation(DhcpHost,
primaryjoin=(cast
(powerdns_records_table.c.content,PGInet)
==dhcp_hosts_table.c.ip_address),
foreign_keys=[powerdns_records_table.c.content],
remote_side=[dhcp_hosts_table.c.ip_address],
viewonly=True,
),
}
)
now, the "viewonly" eliminates your "syncrule" issue. remote_side
currently gives the lazyloader more information on which to build a
lazy clause (works for eager too), and i can make it check for "CAST"
to work around this issue (though id like it to work for any SQL
function too).
but since viewonly, this wont help you with a flush(). if i made
"syncrule" accept a manual argument, such as a callable which you
would define to say "destination.content = str(source.ip_address)",
that would be a generalized way for there to be any kind of
functional stuff indicated within a primaryjoin condition.
in the case of CAST specifically, we do have some awareness that we
need to go from PGInet -> string when setting DhcpHost's "content"
attribute...but i dont like to redefine DB functionality on the
Python side since we cant easily generalize it.
ive added some comments to this effect to the ticket. this feature
would be better in the 0.4 series, which has several weeks before
release though is available via SVN. does that work for you ?
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