Identifiers are stored in
mysqldatabase tables (user,db, and so forth) usingutf8, but identifiers can contain only characters in the Basic Multilingual Plane (BMP). Supplementary characters are not permitted in identifiers.The
ucs2,utf16, andutf32character sets have the following restrictions:They cannot be used as a client character set, which means that they do not work for
SET NAMESorSET CHARACTER SET. (See Section 9.1.4, “Connection Character Sets and Collations”.)It is currently not possible to use
LOAD DATA INFILEto load data files that use these character sets.FULLTEXTindexes cannot be created on a column that uses any of these character sets. However, you can performIN BOOLEAN MODEsearches on the column without an index.
The
REGEXPandRLIKEoperators 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.