Handling multibyte character sets in SQL Loader.

12 Oct 2023

When working with multibyte character sets in SQL Loader, it is important to ensure that the data is properly encoded and loaded into the database. This is especially crucial when dealing with languages such as Chinese, Japanese, or Korean, which use multibyte characters.

Understanding Character Encoding

Character encoding is the process of mapping characters to numeric values in order to represent them in a computer system. Multibyte character sets, also known as double-byte character sets (DBCS), use two bytes to represent each character, allowing for a wider range of characters to be supported.

Configuring SQL Loader for Multibyte Character Sets

To handle multibyte character sets in SQL Loader, follow these steps:

Specify the character set in the control file:

OPTIONS (DIRECT=TRUE, ERRORS=5000, SILENT=(FEEDBACK))
LOAD DATA CHARACTERSET UTF8
INFILE 'data.csv'

Replace UTF8 with the appropriate character set for your data.

Set the NLS_LANG environment variable:

export NLS_LANG=AMERICAN_AMERICA.AL32UTF8

This ensures that the correct character set is used when SQL Loader interacts with the database.

Encode the data correctly in the input file:

For example, if your input file is in UTF-8 encoding, make sure the characters are properly encoded.

Handling Errors

When loading data with multibyte characters, there is a possibility of encountering errors. Here are some common issues and how to handle them:

Data truncation: If the database column is not wide enough to store multibyte characters, data truncation may occur. To avoid this, ensure that the database columns are defined with the appropriate width.
Invalid characters: If invalid characters are present in the data, you can handle them using the BADFILE clause in the control file. This allows you to redirect the records with invalid characters to a separate file for further analysis.
Character set conversion errors: If the character set specified in the control file does not match the actual character set of the data, SQL Loader may encounter character set conversion errors. Make sure the specified character set is correct and matches the data.

Conclusion

Handling multibyte character sets in SQL Loader requires proper configuration and attention to detail. By following the steps outlined above, you can ensure that your data is properly encoded and loaded into the database, avoiding any potential issues with character set conversion or data truncation.

#sqlloader #multibytecharactersets