Oracle Error Message
SQL*Loader-00402: Unable to determine length of column string from specification
Reason for the Error
The specified datatype does not have an implied length (for example, a numeric external or RAW datatype), it is not specified with delimiters, no length was specified, and a length cannot be determined from a POSITION clause.
Solution
If a POSITION clause is specified, adding an end location to it produces a length specification. This clause then has the form POSITION(start:end) A length can also specified after the datatype, as in INTEGER EXTERNAL (6) Finally, the field could be specified with delimiters, or the datatype changed to one that has an implied length.