Data Source Connections and Data Access Administration
Connection types and query modes
Cognos Analytics connects to relational sources through JDBC and to OLAP sources such as TM1, Essbase, SAP BW, and Analysis Services. Dynamic Query Mode (DQM) is the modern query engine and is required for many OLAP and dimensionally modeled relational features; Compatible Query Mode exists for older scenarios.
Core rules
- Create a data source connection, then a signon for credentials; use external namespace signons for single sign-on where supported.
- Test the connection after any driver, database, or network change.
- DQM uses the XQE query service; check xqe.log when queries fail.
- Data server connections support data modules and data sets; they are distinct from package-based data source connections.
- Apply permissions to data source connections so only intended groups can execute queries.
Worked example
A report fails with an XQE connection error. The administrator tests the data source connection, confirms the JDBC driver version, checks the signon credentials, and reviews xqe.log. The driver was upgraded but the connection URL still points to the old host, so correcting the URL resolves the failure.
Traps
Using CQM for features that require DQM; storing credentials in report specifications; forgetting to test after a driver upgrade; and granting broad data source access through Everyone.