Identifiers are stored in mysql database
tables (user, db, and so
forth) using utf8, but identifiers can
contain only characters in the Basic Multilingual Plane (BMP).
Supplementary characters are not permitted in identifiers.
The ucs2 character sets has the following
restrictions:
It cannot be used as a client character set, which means
that it does not work for SET NAMES or
SET CHARACTER SET. (See
Section 10.1.4, “Connection Character Sets and Collations”.)
It is currently not possible to use
LOAD DATA
INFILE to load data files that use this
character set.
FULLTEXT indexes cannot be created on a
column that this character set. However, you can perform
IN BOOLEAN MODE searches on the column
without an index.
The use of ENCRYPT() with
this character set is not recommended because the
underlying system call expects a string terminated by a
zero byte.
The REGEXP and
RLIKE
operators work in byte-wise fashion, so they are not
multi-byte safe and may produce unexpected results with
multi-byte character sets. In addition, these operators
compare characters by their byte values and accented
characters may not compare as equal even if a given collation
treats them as equal.