ruby - saving utf8mb4 strings to mysql -

i have json string has utf8mb4 characters. first parse json, , encode result json. after save resulting json mysql database. (this simplified flow of execution, there real-life reason why first parse json , encode back).

the problem database ends prefix of json string put there , cut off right @ first utf8mb4 character.

here code:

require 'json' require 'mysql2'  tablename = 'my_table'  settings = {   :database => "my_database",   :host => "localhost",   :password => "my_password",   :username => "my_username" }  @database = mysql2::client.new settings @json = %q({"test":"begin \ud83d\ude04\ud83d\udc4d\ud83d\udc4f\ud83d\udd14 end"})  begin   obj = json.parse @json rescue json::parsererror => e   @json.force_encoding 'utf-8'   encoded = @json.valid_encoding? ? @json : @json.encode!('utf-8', invalid: :replace, undef: :replace)   obj = json.parse encoded end  q = "create table if not exists `#{tablename}` (json text not null) engine=innodb default charset=utf8" @database.query q  text = @database.escape json.generate obj q = "insert ignore `#{tablename}` (json) values('#{text}')" @database.query q  q = "select * `#{tablename}`" rs = @database.query q  rs.each {|r|   p r } 

the output is:

{"json"=>"{\"test\":\"begin "} 

i have no idea why happens, appreciate help!

thanks @muistooshort helping me find way fix this:

... settings = {   ...   :encoding => 'utf8mb4' } ... q = "create table ... default charset=utf8mb4" ... 

this works engines support utf8mb4 of course.