mysql:Incorrect string value: '\xF0\x9F\x98\xB8' for column

mysql:Incorrect string value: ‘\xF0\x9F\x98\xB8’ for column
原因是ios平台的emoji不受mysql当前字符集支持。
@seehttp://dev.mysql.com/doc/refman/5.5/en/charset-unicode-utf8mb4.html

10.1.10.6 The utf8mb4 Character Set (4-Byte UTF-8 Unicode Encoding)
The character set named utf8 uses a maximum of three bytes per character and contains only BMP characters.
As of MySQL 5.5.3, the utf8mb4 character set uses a maximum of four bytes per character supports supplemental characters:
For a BMP character, utf8 and utf8mb4 have identical storage characteristics: same code values, same encoding, same length.
For a supplementary character, utf8 cannot store the character at all, while utf8mb4 requires four bytes to store it. You need not worry about converting characters or losing data when upgrading utf8 data from older versions of MySQL.
基本多文种平面（Basic Multilingual Plane, BMP），或称第0平面或0号平面（Plane 0），是Unicode中的一个编码区段。编码从U+0000至U+FFFF。