If you use SQL*Loader conventional path or the Oracle Call Interface (OCI) to load data into VARRAYs or into primary-key-based REFs, and the data being loaded is in a different character set than the database character set, then problems such as the following might occur:
Rows might be rejected because a field is too large for the database column, but in reality the field is not too large.
A load might be abnormally terminated without any rows being loaded, when only the field that really was too large should have been rejected.
Rows might be reported as loaded correctly, but the primary-key-based REF columns are returned as blank when they are selected with SQL*Plus.
To avoid these problems, set the client character set (using the NLS_LANG environment variable) to the database character set before you load the data.