MySQL 5.1: mysql/src/5.1-dbg/sql/sql_trigger.h Source File
mysql/src/5.1-dbg/sql/sql_trigger.h

00001 /* Copyright (C) 2004-2005 MySQL AB
00002 
00003    This program is free software; you can redistribute it and/or modify
00004    it under the terms of the GNU General Public License as published by
00005    the Free Software Foundation; either version 2 of the License, or
00006    (at your option) any later version.
00007 
00008    This program is distributed in the hope that it will be useful,
00009    but WITHOUT ANY WARRANTY; without even the implied warranty of
00010    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00011    GNU General Public License for more details.
00012 
00013    You should have received a copy of the GNU General Public License
00014    along with this program; if not, write to the Free Software
00015    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA */
00016 
00017 
00018 /*
00019   This class holds all information about triggers of table.
00020 
00021   QQ: Will it be merged into TABLE in future ?
00022 */
00023 
00024 class Table_triggers_list: public Sql_alloc
00025 {
00026   /* Triggers as SPs grouped by event, action_time */
00027   sp_head *bodies[TRG_EVENT_MAX][TRG_ACTION_MAX];
00028   /*
00029     Heads of the lists linking items for all fields used in triggers
00030     grouped by event and action_time.
00031   */
00032   Item_trigger_field *trigger_fields[TRG_EVENT_MAX][TRG_ACTION_MAX];
00033   /*
00034     Copy of TABLE::Field array with field pointers set to TABLE::record[1]
00035     buffer instead of TABLE::record[0] (used for OLD values in on UPDATE
00036     trigger and DELETE trigger when it is called for REPLACE).
00037   */
00038   Field             **record1_field;
00039   /*
00040     During execution of trigger new_field and old_field should point to the
00041     array of fields representing new or old version of row correspondingly
00042     (so it can point to TABLE::field or to Tale_triggers_list::record1_field)
00043   */
00044   Field             **new_field;
00045   Field             **old_field;
00046   /* TABLE instance for which this triggers list object was created */
00047   TABLE *table;
00048   /*
00049     Names of triggers.
00050     Should correspond to order of triggers on definitions_list,
00051     used in CREATE/DROP TRIGGER for looking up trigger by name.
00052   */
00053   List<LEX_STRING>  names_list;
00054   /*
00055     List of "ON table_name" parts in trigger definitions, used for
00056     updating trigger definitions during RENAME TABLE.
00057   */
00058   List<LEX_STRING>  on_table_names_list;
00059   /*
00060     Key representing triggers for this table in set of all stored
00061     routines used by statement.
00062     TODO: We won't need this member once triggers namespace will be
00063     database-wide instead of table-wide because then we will be able
00064     to use key based on sp_name as for other stored routines.
00065   */
00066   LEX_STRING        sroutines_key;
00067 
00068   /*
00069     Grant information for each trigger (pair: subject table, trigger definer).
00070   */
00071   GRANT_INFO        subject_table_grants[TRG_EVENT_MAX][TRG_ACTION_MAX];
00072 
00073 public:
00074   /*
00075     Field responsible for storing triggers definitions in file.
00076     It have to be public because we are using it directly from parser.
00077   */
00078   List<LEX_STRING>  definitions_list;
00079   /*
00080     List of sql modes for triggers
00081   */
00082   List<ulonglong> definition_modes_list;
00083 
00084   List<LEX_STRING>  definers_list;
00085 
00086   Table_triggers_list(TABLE *table_arg):
00087     record1_field(0), table(table_arg)
00088   {
00089     bzero((char *)bodies, sizeof(bodies));
00090     bzero((char *)trigger_fields, sizeof(trigger_fields));
00091     bzero((char *)&subject_table_grants, sizeof(subject_table_grants));
00092   }
00093   ~Table_triggers_list();
00094 
00095   bool create_trigger(THD *thd, TABLE_LIST *table,
00096                       LEX_STRING *definer_user,
00097                       LEX_STRING *definer_host);
00098   bool drop_trigger(THD *thd, TABLE_LIST *table);
00099   bool process_triggers(THD *thd, trg_event_type event,
00100                         trg_action_time_type time_type,
00101                         bool old_row_is_record1);
00102   bool get_trigger_info(THD *thd, trg_event_type event,
00103                         trg_action_time_type time_type,
00104                         LEX_STRING *trigger_name, LEX_STRING *trigger_stmt,
00105                         ulong *sql_mode,
00106                         LEX_STRING *definer);
00107 
00108   static bool check_n_load(THD *thd, const char *db, const char *table_name,
00109                            TABLE *table, bool names_only);
00110   static bool drop_all_triggers(THD *thd, char *db, char *table_name);
00111   static bool change_table_name(THD *thd, const char *db,
00112                                 const char *old_table,
00113                                 const char *new_db,
00114                                 const char *new_table);
00115   bool has_delete_triggers()
00116   {
00117     return (bodies[TRG_EVENT_DELETE][TRG_ACTION_BEFORE] ||
00118             bodies[TRG_EVENT_DELETE][TRG_ACTION_AFTER]);
00119   }
00120 
00121   bool has_before_update_triggers()
00122   {
00123     return test(bodies[TRG_EVENT_UPDATE][TRG_ACTION_BEFORE]);
00124   }
00125 
00126   void set_table(TABLE *new_table);
00127 
00128   void mark_fields_used(trg_event_type event);
00129 
00130   friend class Item_trigger_field;
00131   friend int sp_cache_routines_and_add_tables_for_triggers(THD *thd, LEX *lex,
00132                                                             TABLE_LIST *table);
00133 
00134 private:
00135   bool prepare_record1_accessors(TABLE *table);
00136   LEX_STRING* change_table_name_in_trignames(const char *db_name,
00137                                              LEX_STRING *new_table_name,
00138                                              LEX_STRING *stopper);
00139   bool change_table_name_in_triggers(THD *thd,
00140                                      const char *db_name,
00141                                      LEX_STRING *old_table_name,
00142                                      LEX_STRING *new_table_name);
00143 };
00144 
00145 extern const LEX_STRING trg_action_time_type_names[];
00146 extern const LEX_STRING trg_event_type_names[];
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