database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-08-01 03:47:19 +03:00
Code Activity

Fix for bug #5888 "Triggers with nonexistent columns cause packets

Browse Source 
out of order". (final version)

Now instead of binding Item_trigger_field to TABLE objects during
trigger definition parsing at table open, we perform pass through
special list of all such objects in trigger. This allows easily check
all references to fields in old/new version of row in trigger during
execution of CREATE TRIGGER statement (this is more courtesy for users
since we can't check everything anyway).
We also report that such reference is bad by returning error from
Item_trigger_field::fix_fields() method (instead of setup_field())
This means that if trigger is broken we will bark during trigger
execution instead of trigger definition parsing at table open.
(i.e. now we allow to open tables with broken triggers).
This commit is contained in:
dlenev@brandersnatch.localdomain
2004-11-24 12:24:02 +03:00
parent 8c401b5569
commit d201074611
13 changed files with 165 additions and 96 deletions
Download Patch File Download Diff File Expand all files Collapse all files

107
sql/sql_trigger.cc
View File

@ -136,6 +136,7 @@ bool Table_triggers_list::create_trigger(THD *thd, TABLE_LIST *tables)
char dir_buff[FN_REFLEN], file_buff[FN_REFLEN];
LEX_STRING dir, file;
LEX_STRING *trg_def, *name;
Item_trigger_field *trg_field;
List_iterator_fast<LEX_STRING> it(names_list);
/* We don't allow creation of several triggers of the same type yet */
@ -156,6 +157,31 @@ bool Table_triggers_list::create_trigger(THD *thd, TABLE_LIST *tables)
}
}
/*
Let us check if all references to fields in old/new versions of row in
this trigger are ok.
NOTE: We do it here more from ease of use standpoint. We still have to
do some checks on each execution. E.g. we can catch privilege changes
only during execution. Also in near future, when we will allow access
to other tables from trigger we won't be able to catch changes in other
tables...
To simplify code a bit we have to create Fields for accessing to old row
values if we have ON UPDATE trigger.
*/
if (!old_field && lex->trg_chistics.event == TRG_EVENT_UPDATE &&
prepare_old_row_accessors(table))
return 1;
for (trg_field= (Item_trigger_field *)(lex->trg_table_fields.first);
trg_field; trg_field= trg_field->next_trg_field)
{
trg_field->setup_field(thd, table, lex->trg_chistics.event);
if (trg_field->fix_fields(thd, (TABLE_LIST *)0, (Item **)0))
return 1;
}
/*
Here we are creating file with triggers and save all triggers in it.
sql_create_definition_file() files handles renaming and backup of older
@ -274,6 +300,44 @@ Table_triggers_list::~Table_triggers_list()
}
/*
Prepare array of Field objects which will represent OLD.* row values in
ON UPDATE trigger (by referencing to record[1] instead of record[0]).
SYNOPSIS
prepare_old_row_accessors()
table - pointer to TABLE object for which we are creating fields.
RETURN VALUE
False - success
True - error
*/
bool Table_triggers_list::prepare_old_row_accessors(TABLE *table)
{
Field **fld, **old_fld;
if (!(old_field= (Field **)alloc_root(&table->mem_root,
(table->fields + 1) *
sizeof(Field*))))
return 1;
for (fld= table->field, old_fld= old_field; *fld; fld++, old_fld++)
{
/*
QQ: it is supposed that it is ok to use this function for field
cloning...
*/
if (!(*old_fld= (*fld)->new_field(&table->mem_root, table)))
return 1;
(*old_fld)->move_field((my_ptrdiff_t)(table->record[1] -
table->record[0]));
}
*old_fld= 0;
return 0;
}
/*
Check whenever .TRG file for table exist and load all triggers it contains.
@ -317,7 +381,6 @@ bool Table_triggers_list::check_n_load(THD *thd, const char *db,
if (!strncmp(triggers_file_type.str, parser->type()->str,
parser->type()->length))
{
Field **fld, **old_fld;
Table_triggers_list *triggers=
new (&table->mem_root) Table_triggers_list();
@ -330,31 +393,10 @@ bool Table_triggers_list::check_n_load(THD *thd, const char *db,
table->triggers= triggers;
/*
We have to prepare array of Field objects which will represent OLD.*
row values by referencing to record[1] instead of record[0]
TODO: This could be avoided if there is no ON UPDATE trigger.
*/
if (!(triggers->old_field=
(Field **)alloc_root(&table->mem_root, (table->fields + 1) *
sizeof(Field*))))
/* TODO: This could be avoided if there is no ON UPDATE trigger. */
if (triggers->prepare_old_row_accessors(table))
DBUG_RETURN(1);
for (fld= table->field, old_fld= triggers->old_field; *fld;
fld++, old_fld++)
{
/*
QQ: it is supposed that it is ok to use this function for field
cloning...
*/
if (!(*old_fld= (*fld)->new_field(&table->mem_root, table)))
DBUG_RETURN(1);
(*old_fld)->move_field((my_ptrdiff_t)(table->record[1] -
table->record[0]));
}
*old_fld= 0;
List_iterator_fast<LEX_STRING> it(triggers->definitions_list);
LEX_STRING *trg_create_str, *trg_name_str;
char *trg_name_buff;
@ -365,7 +407,7 @@ bool Table_triggers_list::check_n_load(THD *thd, const char *db,
while ((trg_create_str= it++))
{
lex_start(thd, (uchar*)trg_create_str->str, trg_create_str->length);
lex.trg_table= table;
if (yyparse((void *)thd) || thd->is_fatal_error)
{
/*
@ -400,6 +442,21 @@ bool Table_triggers_list::check_n_load(THD *thd, const char *db,
if (triggers->names_list.push_back(trg_name_str, &table->mem_root))
goto err_with_lex_cleanup;
/*
Let us bind Item_trigger_field objects representing access to fields
in old/new versions of row in trigger to Field objects in table being
opened.
We ignore errors here, because if even something is wrong we still will
be willing to open table to perform some operations (e.g. SELECT)...
Anyway some things can be checked only during trigger execution.
*/
for (Item_trigger_field *trg_field=
(Item_trigger_field *)(lex.trg_table_fields.first);
trg_field;
trg_field= trg_field->next_trg_field)
trg_field->setup_field(thd, table, lex.trg_chistics.event);
lex_end(&lex);
}
thd->lex= old_lex;