If they are not the same, Heterogeneous Services tries to translate the character set of the non-Oracle data source to the Oracle8 character set, and vice versa. This can degrade performance, and in some cases Heterogeneous Services will not be able to translate a character from one character set to another. These are controlled by the session settings in the Oracle server. The level of National Language Support between the Oracle8 server and the non-Oracle data source depends on how the driver is implemented. See the installation and users' guide for your platform for more information about the level of National Language Support.
Date formats can be language independent.
This abbreviation is very much language dependent. Heterogeneous Services will assume that character date values fetched from the non-Oracle system are in this format. Also, Heterogeneous Services will sent character date bind values in this format to the non-Oracle system. The value never exceeds the number of open cursors in the Oracle server. When the cache is full, the first slot in the cache is reused, then the second, and so on.