Character set conversion causes all SQL statements to be converted to the database character set before parsing and execution.
A side-effect of this conversion is that any characters in the SQL statement that cannot be converted to the database character set are converted to a substitution character. A SQL statement with an arbitrary Unicode character can be executed in one of the following ways:
Use the UNISTR function to specify the Unicode character values
Use a host variable to specify the Unicode character values
Use UTF-8 as the database character set
If you select UTF8BIN as the char collation, the database character set is UTF-8. If you select UCA as the CHAR collation, you can choose UTF-8 as the encoding.
The Unicode Collation Algorithm (UCA) provides advanced comparison, ordering, and case conversion, but it can affect performance. Although UTF8BIN is space-efficient and fast, the sort order and comparison is binary. Specify the char collation as UTF8BIN if you require Unicode characters in your SQL statements, but do not need the full power of UCA for sorting and comparison. Use UCA only when necessary, by using the SORTKEY and COMPARE functions.