Question

I’ve got a table where all fields are set to ‘utf8_general_ci’. There’s a trigger on the table which captures data changes and inserts them into a ‘log’ table.

The trigger has a variable (var_row_data) which stores the updated row’s old data, and that variable is then inserted into the log table. However, somehow MySQL throws an exception each time a special character (e.g ł and ń) is part of the data stored in the trigger variable.

Am I missing something about trigger variables and their encoding? Connections are using utf8, tables are utf8, webpages are utf8. In short; MySQL handles the special characters just fine but once the trigger tries to store the special characters it all goes wrong.

Does anyone have any experience with this? There’s apparently something going on with the trigger variables, but I just don’t understand how to get around it.

For the record, here’s the trigger:

DROP TRIGGER IF EXISTS `SYM_ON_U_FOR_VRBLS_WBPRD`//
CREATE TRIGGER `SYM_ON_U_FOR_VRBLS_WBPRD` AFTER UPDATE ON `variables`
 FOR EACH ROW begin
                                  DECLARE var_row_data mediumtext;
                                  DECLARE var_old_data mediumtext;
                                  if 1=1 and @sync_triggers_disabled is null then
                                    set var_row_data = concat(
          if(new.`id` is null,'',concat('"',cast(new.`id` as char),'"')),',',
          if(new.`variable` is null,'',concat('"',replace(replace(new.`variable`,'\','\\'),'"','\"'),'"')),',',
          if(new.`value` is null,'',concat('"',replace(replace(new.`value`,'\','\\'),'"','\"'),'"')));
                                    set var_old_data = concat(
          if(old.`id` is null,'',concat('"',cast(old.`id` as char),'"')),',',
          if(old.`variable` is null,'',concat('"',replace(replace(old.`variable`,'\','\\'),'"','\"'),'"')),',',
          if(old.`value` is null,'',concat('"',replace(replace(old.`value`,'\','\\'),'"','\"'),'"')));
                                    if 1=1 then 
                                        insert into trackerdatabase_production_synch.sym_data (table_name, event_type, trigger_hist_id, pk_data, row_data, old_data, channel_id, transaction_id, source_node_id, external_data, create_time)
                                        values(
                                          'variables',
                                          'U',
                                          18,
                                          concat(
          if(old.`id` is null,'',concat('"',cast(old.`id` as char),'"'))
                                           ),
                                          var_row_data,
                                          var_old_data,
                                          'default', trackerdatabase_production_synch.sym_transaction_id(), @sync_node_disabled,
                                          null,
                                          CURRENT_TIMESTAMP
                                        );
                                    end if;
                                  end if;
                                end
//

Answer 1

Perhaps:

DECLARE var_row_data MEDIUMTEXT CHARACTER SET utf8;