I have a model which has sites and servers with a many-to-many
relation described by site_servers as follows:
# Global table of known sites
db.define_table('sites',
Field('uuid', 'string', length=64, default=str(uuid.uuid4()),
writable=False),
Field('last_modified', 'datetime', default=request.now,
update=request.now, writable=False, readable=False),
Field('name', 'string', length=16, required=True, notnull=True,
unique=True, label='Site name'),
Field('long_name', 'string', length=64, unique=True, label='Site
full name'),
format='%(name)s'
)
# Global table of known servers
db.define_table('servers',
Field('uuid', 'string', length=64, default=str(uuid.uuid4()),
writable=False),
Field('last_modified', 'datetime', default=request.now,
update=request.now, writable=False, readable=False),
Field('hostname', 'string', length=64, required=True,
notnull=True, unique=True, label='Hostname:'),
format='%(hostname)s'
)
# Global table showing which servers perform known functions for which
sites.
# The default is a server provides all services.
db.define_table('site_servers',
Field('uuid', 'string', length=64, default=str(uuid.uuid4()),
writable=False),
Field('last_modified', 'datetime', default=request.now,
update=request.now, writable=False, readable=False),
Field('site_uuid', 'string', length=64),
Field('server_uuid', 'string', length=64),
Field('web_server', 'boolean', default=True),
Field('archiver', 'boolean', default=True)
)
db.site_servers.site_uuid.requires = IS_IN_DB(db, 'sites.uuid', '%
(name)s')
db.site_servers.server_uuid.requires = IS_IN_DB(db, 'servers.uuid', '%
(hostname)s')
sites_and_servers = db((db.sites.uuid==db.site_servers.site_uuid) &
(db.servers.uuid==db.site_servers.server_uuid))
The problem is this line that should be used to test for uniqueness of
the site_servers rows so I don't get duplicate entries in the join
table causes the server line of the site_servers insert form to change
from a drop down selecting from existing servers to a text input line.
# Test for uniqueness across site_uuid and server_uuid
db.site_servers.server_uuid.requires = IS_NOT_IN_DB(db
(db.site_servers.site_uuid==request.vars.site_uuid),db.site_servers.server_uuid)
I took thie problem line from several other posts, however they were
not involving uuid and timestamp tables meant for global use across
multiple installations of the database.
I have trimmed some fields from the model to simplify the definition.
Also the example in the DAL chapter third edition of the book under
the heading CSV and Remote Database Synchronization shows the
'modified_on' field setting of default=now which results in undefined
variable now. I believe that should be default=request.now
Thanks for any advice
Ron
