Short answer, it's the ASN. In the model, you give the entity a data path. In the asn, you map that data path (Usually $DEF) to a database path. $DEF = MSS:dsn_name:database_name|user|password Sometimes, this is actually mapped via the urouter $DEF=TCP:server+port|userver|password|UST which is then passed on to userver on the named server, using urouter.asn which then has another asn which maps the data to the database as above. Sometimes, there are multiple paths defined in the asn, and the [ENTITIES] section redirects different entities to different paths by name. [PATHS] $JIM=MSS:dsn_name:database1|user|password $BILL=MSS:dsn_name:database2|user|password $FRED=OD0:dsn_name2:|user|password [ENTITIES] *.SYSTEM=$JIM:*.SYSTEM CUSTOMERS.ACCOUNTS=$BILL:CUSTOMERS.ACCOUNTS *.ACCOUNTS=$FRED:*.ACCOUNTS The above will send all queries/updates for entities in the model system to JIM (i.e. database 1) all queries/updates for customer.accounts to BILL (i.e. database 2) and all queries/updates for the other entities in the accounts model to FRED (i.e. the ODBC database on dsn_name2) Any that aren't mentioned in [ENTITIES] are routed via the path defined in the model, as above. Iain