The SQL*Loader control file itself is assumed to be in the character set specified for your session by the NLS_LANG parameter. If the control file character set is different from the data file character set, then keep the following issue in mind. Delimiters and comparison clause values specified in the SQL*Loader control file as character strings are converted from the control file character set to the data file character set before any comparisons are made. To ensure that the specifications are correct, you may prefer to specify hexadecimal strings, rather than character string values.
If hexadecimal strings are used with a data file in the UTF-16 Unicode encoding, then the byte order is different on a big-endian versus a little-endian system. For example, "," (comma) in UTF-16 on a big-endian system is X'002c'. On a little-endian system it is X'2c00'. SQL*Loader requires that you always specify hexadecimal strings in big-endian format. If necessary, SQL*Loader swaps the bytes before making comparisons. This allows the same syntax to be used in the control file on both a big-endian and a little-endian system.
Record terminators for data files that are in stream format in the UTF-16 Unicode encoding default to "\n" in UTF-16 (that is, 0x000A on a big-endian system and 0x0A00 on a little-endian system). You can override these default settings by using the "STR 'char_str'" or the "STR x'hex_str'" specification on the INFILE line. For example, you could use either of the following to specify that 'ab' is to be used as the record terminator, instead of '\n'.
INFILE myfile.dat "STR 'ab'" INFILE myfile.dat "STR x'00410042'"
Any data included after the BEGINDATA statement is also assumed to be in the character set specified for your session by the NLS_LANG parameter.
For the SQL*Loader data types (CHAR, VARCHAR, VARCHARC, DATE, and EXTERNAL numerics), SQL*Loader supports lengths of character fields that are specified in either bytes (byte-length semantics) or characters (character-length semantics). For example, the specification CHAR(10) in the control file can mean 10 bytes or 10 characters. These are equivalent if the data file uses a single-byte character set. However, they are often different if the data file uses a multibyte character set.
To avoid insertion errors caused by expansion of character strings during character set conversion, use character-length semantics in both the data file and the target database columns.