mahout-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Mirko <idonthaveenoughinformat...@googlemail.com>
Subject GenericJDBCDataModel problem (getItems, getUsers)
Date Wed, 04 Nov 2009 17:04:17 GMT
Hi,
I have problems with the GenericJDBCDataModel. For me, the functions  
getUsers() and getItems() return nothing, although the SQL queries  
used in the functions definitely do return results. All other  
functions in the DataModel work as expected.

The results of the queries used in getUsers() and getItems() look as  
follows:

SQL result for GenericJDBCDataModel.GET_ITEMS_SQL_KEY:

item_id
------------
itemID_A
itemID_B
itemID_C
itemID_D
itemID_E
...

SQL result for GenericJDBCDataModel.GET_USERS_SQL_KEY

item_id		callret-1		user_id
----------------------------------------------
itemID_A	1		userID_X
itemID_B	1		userID_Y
itemID_C	1		userID_Z
...

I think these results should be correct (Preferences are always 1 in  
my data). But the Iterables returned by both functions seem to be empty:

GenericJDBCDataModel dm = new GenericJDBCDataModel(props);
for ( Item item : dm.getItems()){
	System.out.println(item.getID()); //Never reached
}
for ( User user : dm.getUsers()){
	System.out.println(user.getID()); //Never reached
}


I should note that I query an OpenLink Virtuoso RDF store, which uses  
SPARQL queries enclosed in SQL queries. That means that  'columns' and  
'tables' , and thus the variables DEFAULT_PREFERENCE_TABLE,  
DEFAULT_USER_ID_COLUMN, DEFAULT_ITEM_ID_COLUMN and  
DEFAULT_PREFERENCE_COLUMN of AbstractJDBCDataModel don't have any  
meaning. But as I understand the code, they are not required when  
using the GenericJDBCDataModel.

Is it possible that some exception is thrown 'silently' in the  
AbstractJDBCDataModel?

I have no idea where to look for the prob, so thanks for any hints....

Regards,
Mirko




Mime
View raw message