Since the ODBC Driver for eDirectory uses the resources of the workstation for memory and hard disk storage, you can ask for a report that generates more data than your workstation can handle in memory or store on the target drive.
eDirectory can contain a tremendous number of objects. For example, a container object can have
Over 10,000 objects in NetWare 5
Millions of objects in NDS 8
Before requesting data on all objects of a certain type from the top of the tree or from a branch, you should have a rough estimate of how many objects you are requesting data about. If you are generating a report for thousands of objects, you may want to generate multiple reports rather than a single report.
Also, each object in eDirectory contains multiple attributes. For example, User objects in NDS 8 had over 90 attributes. If you add other products which add attributes to User objects, such as ZENworks, the number is even greater. The Novell ODBC Driver for NDS reads the schema to determine the actual number of attributes an object contains, and an SQL query for information on all attributes builds a table with all attributes, even those attributes which have no values. Therefore, an SQL query for all attribute information about objects is not recommended. To keep a report to a reasonable size, you need to select specific attributes for the report. To determine which objects have tables and what attributes an object has, see Possible NDS Tables and Columns. You should also be aware that you can request a report that will take a tremendous amount of time to generate. The obvious cause is to request too much data. However, there are other causes. NDS allows data to be replicated and stored in multiple locations which makes it possible to have some data available only from a WAN link. Therefore, to generate reports quickly, you need to have some knowledge of how the NDS database has been replicated and whether replicas of all partitions are stored locally or over WAN links.