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Working With Data Source Connections

You can customize data source connections to meet the needs of users.

Multiple Data Source Connections

If you have access to more than one data source connection in a data source, you are prompted to select a data source connection when you open a Framework Manager project. You can use multiple data source connections in a single data source to facilitate the migration from one environment to another and maintain the integrity of a project.

For example, you can use multiple data source connections to work with metadata from a test data source. Create a new project, using the GoSales data source connection. Create and modify the objects you want in the project, and test to ensure that the project is modeled the way you want. After you close the session, and reopen the Framework Manager project, you can select the production data source connection. When you publish the package to the Cognos 8 server, your users choose which data source connection they want to use in their report.

Multiple connections to the same data source must be defined in Cognos Connection. If you want to support multiple connections for each data source, clear the data source catalog and schema names, and create a connection for each database in Cognos Connection.

Note: If you are working with multiple cubes containing unlike metadata, we recommend that you use separate data sources for each cube. To be able to expand an OLAP package in the Studios, the internal name of both cubes must be the same. If you want to run saved reports that use different data source connections, the cube name, as well as the dimension, hierarchy, level and attribute names, must be the same in both cubes. If you use a single data source with a separate connection for each cube, the internal names of all the cubes must be the same.

For more information about data source connections, see the Administration and Security Guide.

Databases and Sorting Functions

If you use sorting functions such as running-totals in reports, you may need to add a collation sequence to the database connection string to maintain data integrity. Otherwise, when sorting a report that is grouped by one or more columns containing foreign characters, you may get inconsistent results. This is because without the collation sequence information, the default locale is used to sort data, whereas databases may use different collations in their sorting.

To prevent sorting inconsistencies, you must add the correct collation sequence to your database connection string when you create a data source or add a connection.

For example, in Oracle, if you specify the collation sequence as Binary at the database level, you should provide the same collation sequence value in the connection string.

Isolation Levels

The isolation level specifies how transactions that modify the database are handled. By default, the default object gateway is used. Not all types of databases support each isolation level. Some database vendors use different names for the isolation levels.

For OLAP data sources, including SAP BW, the isolation level is read-only.

The following isolation levels are in increasing order of isolation: