Refreshing the Schema in a Data Source View (Analysis Services)
After defining a data source view in an Analysis Services project or database, the schema in an underlying data source may change. These changes are not automatically detected or updated.
When changes occur in the schema of an underlying data source, you can refresh the data source view to incorporate all of the changes to each of the underlying data sources. Refreshing a data source view updates the whole data source view.
Refreshing a data source view incorporates changes from both the primary data source for the data source view, and also any secondary data sources referenced by tables or named queries in the data source view. You must have active connections to all data sources referenced by the data source view to refresh the data source view. The data source view is not refreshed if a connection error occurs for any data source referenced by the data source view.
If there are changes to the schema of the data source view in an underlying data source, Data Source View Designer lists the objects that have changed and the changes that will be made in the data source view. The report lists tables, columns, constraints, and relationships that will be deleted or added in the data source view. The report also lists any named query or calculation that cannot be successfully prepared. The affected objects are listed in a tree view with columns and relationships nested under tables and the type of change (deletion or addition) indicated for each object. The standard data source view object icons indicate the type of object affected.
After you examine the report, you can either accept the changes or cancel the update to reject any changes. You can also save a report of the changes. Refreshing a data source view can delete tables, columns, and relationships and add columns and relationships, but the refreshing process never adds tables. New unique constraints are added to the data source view. If a logical primary key exists for a table in the data source view and a physical key is added to the table in the data source, the logical key is removed and replaced by the physical key.
Refreshing a data source view is based completely on the names of the underlying objects. Therefore, if an underlying object is renamed in the data source, Data Source View Designer treats the renamed object as two separate operations—a deletion and an addition. In this case, you may have to manually add the renamed object back to the data source view. You may also have to re-create relationships or logical primary keys.
|If you are aware that a table has been renamed in a data source, you may want to use the Replace Table command to replace the table with the renamed table before you refresh the data source view. For more information, see Replacing a Table or a Named Query in a Data Source View.|
For step by step procedures on how to refresh a data source view, see How to: Refresh a Data Source View Using Data Source View Designer.