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mariadb/sql/sql_view.cc
unknown 1e623bb9c3 allow merging views with subqueries in WHERE clause (BUG#5504) 
mysql-test/r/view.result:
  test of subqueries in merged views
mysql-test/t/view.test:
  test of subqueries in merged views
sql/item_subselect.h:
  new method tu return place of subquery
sql/sql_lex.cc:
  allow merging views with subqueries in WHERE clause
sql/sql_view.cc:
  allow merging views with subqueries in WHERE clause
2004-10-07 22:54:31 +03:00

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/* Copyright (C) 2004 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "mysql_priv.h"
#include "sql_acl.h"
#include "sql_select.h"
#include "parse_file.h"
#include "sp.h"
static int mysql_register_view(THD *thd, TABLE_LIST *view,
enum_view_create_mode mode);
const char *updatable_views_with_limit_names[]= { "NO", "YES", NullS };
TYPELIB updatable_views_with_limit_typelib=
{
array_elements(updatable_views_with_limit_names)-1, "",
updatable_views_with_limit_names
};
/*
Creating/altering VIEW procedure
SYNOPSIS
mysql_create_view()
thd - thread handler
mode - VIEW_CREATE_NEW, VIEW_ALTER, VIEW_CREATE_OR_REPLACE
RETURN VALUE
0 OK
-1 Error
1 Error and error message given
*/
int mysql_create_view(THD *thd,
enum_view_create_mode mode)
{
LEX *lex= thd->lex;
bool link_to_local;
/* first table in list is target VIEW name => cut off it */
TABLE_LIST *view= lex->unlink_first_table(&link_to_local);
TABLE_LIST *tables= lex->query_tables;
TABLE_LIST *tbl;
SELECT_LEX *select_lex= &lex->select_lex, *sl;
SELECT_LEX_UNIT *unit= &lex->unit;
int res= 0;
DBUG_ENTER("mysql_create_view");
if (lex->proc_list.first ||
lex->result)
{
my_error(ER_VIEW_SELECT_CLAUSE, MYF(0), (lex->result ?
"INTO" :
"PROCEDURE"));
res= -1;
goto err;
}
if (lex->derived_tables ||
lex->variables_used || lex->param_list.elements)
{
my_error((lex->derived_tables ?
ER_VIEW_SELECT_DERIVED :
ER_VIEW_SELECT_VARIABLE), MYF(0));
res= -1;
goto err;
}
#ifndef NO_EMBEDDED_ACCESS_CHECKS
/*
Privilege check for view creation:
- user have CREATE VIEW privilege on view table
- user have DELETE privilege in case of ALTER VIEW or CREATE OR REPLACE
VIEW
- have some (SELECT/UPDATE/INSERT/DELETE) privileges on columns of
underlying tables used on top of SELECT list (because it can be
(theoretically) updated, so it is enough to have UPDATE privilege on
them, for example)
- have SELECT privilege on columns used in expressions of VIEW select
- for columns of underly tables used on top of SELECT list also will be
checked that we have not more privileges on correspondent column of view
table (i.e. user will not get some privileges by view creation)
*/
if ((check_access(thd, CREATE_VIEW_ACL, view->db, &view->grant.privilege,
0, 0) ||
grant_option && check_grant(thd, CREATE_VIEW_ACL, view, 0, 1, 0)) ||
(mode != VIEW_CREATE_NEW &&
(check_access(thd, DELETE_ACL, view->db, &view->grant.privilege,
0, 0) ||
grant_option && check_grant(thd, DELETE_ACL, view, 0, 1, 0))))
DBUG_RETURN(1);
for (sl= select_lex; sl; sl= sl->next_select())
{
for (tbl= sl->get_table_list(); tbl; tbl= tbl->next_local)
{
/*
Ensure that we have some privileges on this table, more strict check
will be done on column level after preparation,
*/
if (check_some_access(thd, VIEW_ANY_ACL, tbl))
{
my_printf_error(ER_TABLEACCESS_DENIED_ERROR,
ER(ER_TABLEACCESS_DENIED_ERROR),
MYF(0),
"ANY",
thd->priv_user,
thd->host_or_ip,
tbl->real_name);
DBUG_RETURN(-1);
}
/*
Mark this table as a table which will be checked after the prepare
phase
*/
tbl->table_in_first_from_clause= 1;
/*
We need to check only SELECT_ACL for all normal fields, fields for
which we need "any" (SELECT/UPDATE/INSERT/DELETE) privilege will be
checked later
*/
tbl->grant.want_privilege= SELECT_ACL;
/*
Make sure that all rights are loaded to the TABLE::grant field.
tbl->real_name will be correct name of table because VIEWs are
not opened yet.
*/
fill_effective_table_privileges(thd, &tbl->grant, tbl->db,
tbl->real_name);
}
}
if (&lex->select_lex != lex->all_selects_list)
{
/* check tables of subqueries */
for (tbl= tables; tbl; tbl= tbl->next_global)
{
if (!tbl->table_in_first_from_clause)
{
if (check_access(thd, SELECT_ACL, tbl->db,
&tbl->grant.privilege, 0, 0) ||
grant_option && check_grant(thd, SELECT_ACL, tbl, 0, 1, 0))
{
res= 1;
goto err;
}
}
}
}
/*
Mark fields for special privilege check ("any" privilege)
*/
for (sl= select_lex; sl; sl= sl->next_select())
{
List_iterator_fast<Item> it(sl->item_list);
Item *item;
while ((item= it++))
{
Item_field *field;
if ((field= item->filed_for_view_update()))
field->any_privileges= 1;
}
}
#endif
if ((res= open_and_lock_tables(thd, tables)))
DBUG_RETURN(res);
/*
check that tables are not temporary and this VIEW do not used in query
(it is possible with ALTERing VIEW)
*/
for (tbl= tables; tbl; tbl= tbl->next_global)
{
/* is this table temporary and is not view? */
if (tbl->table->tmp_table != NO_TMP_TABLE && !tbl->view)
{
my_error(ER_VIEW_SELECT_TMPTABLE, MYF(0), tbl->alias);
res= -1;
goto err;
}
/* is this table view and the same view which we creates now? */
if (tbl->view &&
strcmp(tbl->view_db.str, view->db) == 0 &&
strcmp(tbl->view_name.str, view->real_name) == 0)
{
my_error(ER_NO_SUCH_TABLE, MYF(0), tbl->view_db.str, tbl->view_name.str);
res= -1;
goto err;
}
/*
Copy the privileges of the underlying VIEWs which were filled by
fill_effective_table_privileges
(they were not copied at derived tables processing)
*/
tbl->table->grant.privilege= tbl->grant.privilege;
}
/* prepare select to resolve all fields */
lex->view_prepare_mode= 1;
if (unit->prepare(thd, 0, 0))
{
/*
some errors from prepare are reported to user, if is not then
it will be checked after err: label
*/
res= 1;
goto err;
}
/* view list (list of view fields names) */
if (lex->view_list.elements)
{
List_iterator_fast<Item> it(select_lex->item_list);
List_iterator_fast<LEX_STRING> nm(lex->view_list);
Item *item;
LEX_STRING *name;
if (lex->view_list.elements != select_lex->item_list.elements)
{
my_message(ER_VIEW_WRONG_LIST, ER(ER_VIEW_WRONG_LIST), MYF(0));
goto err;
}
while ((item= it++, name= nm++))
item->set_name(name->str, name->length, system_charset_info);
}
/* Test absence of duplicates names */
{
Item *item;
List_iterator_fast<Item> it(select_lex->item_list);
it++;
while ((item= it++))
{
Item *check;
List_iterator_fast<Item> itc(select_lex->item_list);
while ((check= itc++) && check != item)
{
if (strcmp(item->name, check->name) == 0)
{
my_error(ER_DUP_FIELDNAME, MYF(0), item->name);
DBUG_RETURN(-1);
}
}
}
}
#ifndef NO_EMBEDDED_ACCESS_CHECKS
/*
Compare/check grants on view with grants of underlying tables
*/
for (sl= select_lex; sl; sl= sl->next_select())
{
char *db= view->db ? view->db : thd->db;
List_iterator_fast<Item> it(sl->item_list);
Item *item;
fill_effective_table_privileges(thd, &view->grant, db,
view->real_name);
while ((item= it++))
{
Item_field *fld;
uint priv= (get_column_grant(thd, &view->grant, db,
view->real_name, item->name) &
VIEW_ANY_ACL);
if ((fld= item->filed_for_view_update()))
{
/*
Do we have more privileges on view field then underlying table field?
*/
if ((~fld->have_privileges & priv))
{
/* VIEW column has more privileges */
my_printf_error(ER_COLUMNACCESS_DENIED_ERROR,
ER(ER_COLUMNACCESS_DENIED_ERROR),
MYF(0),
"create view",
thd->priv_user,
thd->host_or_ip,
item->name,
view->real_name);
DBUG_RETURN(-1);
}
}
}
}
#endif
if (wait_if_global_read_lock(thd, 0, 0))
{
res= -1;
goto err;
}
VOID(pthread_mutex_lock(&LOCK_open));
res= mysql_register_view(thd, view, mode);
VOID(pthread_mutex_unlock(&LOCK_open));
start_waiting_global_read_lock(thd);
if (res)
goto err;
send_ok(thd);
lex->link_first_table_back(view, link_to_local);
return 0;
err:
thd->proc_info= "end";
lex->link_first_table_back(view, link_to_local);
unit->cleanup();
if (thd->net.report_error)
res= -1;
DBUG_RETURN(res);
}
/* index of revision number in following table */
static const int revision_number_position= 5;
/* index of last required parameter for making view */
static const int required_view_parameters= 7;
/*
table of VIEW .frm field descriptors
Note that one should NOT change the order for this, as it's used by
parse()
*/
static File_option view_parameters[]=
{{{(char*) "query", 5}, offsetof(TABLE_LIST, query),
FILE_OPTIONS_STRING},
{{(char*) "md5", 3}, offsetof(TABLE_LIST, md5),
FILE_OPTIONS_STRING},
{{(char*) "updatable", 9}, offsetof(TABLE_LIST, updatable_view),
FILE_OPTIONS_ULONGLONG},
{{(char*) "algorithm", 9}, offsetof(TABLE_LIST, algorithm),
FILE_OPTIONS_ULONGLONG},
{{"with_check_option", 17}, offsetof(TABLE_LIST, with_check),
FILE_OPTIONS_ULONGLONG},
{{(char*) "revision", 8}, offsetof(TABLE_LIST, revision),
FILE_OPTIONS_REV},
{{(char*) "timestamp", 9}, offsetof(TABLE_LIST, timestamp),
FILE_OPTIONS_TIMESTAMP},
{{(char*)"create-version", 14},offsetof(TABLE_LIST, file_version),
FILE_OPTIONS_ULONGLONG},
{{(char*) "source", 6}, offsetof(TABLE_LIST, source),
FILE_OPTIONS_ESTRING},
{{NULL, 0}, 0,
FILE_OPTIONS_STRING}
};
static LEX_STRING view_file_type[]= {{(char*)"VIEW", 4}};
/*
Register VIEW (write .frm & process .frm's history backups)
SYNOPSIS
mysql_register_view()
thd - thread handler
view - view description
mode - VIEW_CREATE_NEW, VIEW_ALTER, VIEW_CREATE_OR_REPLACE
RETURN
0 OK
-1 Error
1 Error and error message given
*/
static int mysql_register_view(THD *thd, TABLE_LIST *view,
enum_view_create_mode mode)
{
char buff[4096];
String str(buff,(uint32) sizeof(buff), system_charset_info);
char md5[33];
bool can_be_merged;
char dir_buff[FN_REFLEN], file_buff[FN_REFLEN];
LEX_STRING dir, file;
DBUG_ENTER("mysql_register_view");
/* print query */
str.length(0);
{
ulong sql_mode= thd->variables.sql_mode & MODE_ANSI_QUOTES;
thd->variables.sql_mode&= ~MODE_ANSI_QUOTES;
thd->lex->unit.print(&str);
thd->variables.sql_mode|= sql_mode;
}
str.append('\0');
DBUG_PRINT("VIEW", ("View: %s", str.ptr()));
/* print file name */
(void) my_snprintf(dir_buff, FN_REFLEN, "%s/%s/",
mysql_data_home, view->db);
unpack_filename(dir_buff, dir_buff);
dir.str= dir_buff;
dir.length= strlen(dir_buff);
file.str= file_buff;
file.length= (strxnmov(file_buff, FN_REFLEN, view->real_name, reg_ext,
NullS) - file_buff);
/* init timestamp */
if (!view->timestamp.str)
view->timestamp.str= view->timestamp_buffer;
/* check old .frm */
{
char path_buff[FN_REFLEN];
LEX_STRING path;
File_parser *parser;
path.str= path_buff;
fn_format(path_buff, file.str, dir.str, 0, MY_UNPACK_FILENAME);
path.length= strlen(path_buff);
if (!access(path.str, F_OK))
{
if (mode == VIEW_CREATE_NEW)
{
my_error(ER_TABLE_EXISTS_ERROR, MYF(0), view->alias);
DBUG_RETURN(-1);
}
if (!(parser= sql_parse_prepare(&path, &thd->mem_root, 0)))
DBUG_RETURN(1);
if (!parser->ok() ||
strncmp("VIEW", parser->type()->str, parser->type()->length))
{
my_error(ER_WRONG_OBJECT, MYF(0), (view->db ? view->db : thd->db),
view->real_name, "VIEW");
DBUG_RETURN(-1);
}
/*
read revision number
TODO: read dependence list, too, to process cascade/restrict
TODO: special cascade/restrict procedure for alter?
*/
if (parser->parse((gptr)view, &thd->mem_root,
view_parameters + revision_number_position, 1))
{
DBUG_RETURN(thd->net.report_error? -1 : 0);
}
}
else
{
if (mode == VIEW_ALTER)
{
my_error(ER_NO_SUCH_TABLE, MYF(0), view->db, view->alias);
DBUG_RETURN(-1);
}
}
}
/* fill structure */
view->query.str= (char*)str.ptr();
view->query.length= str.length()-1; // we do not need last \0
view->source.str= thd->query;
view->source.length= thd->query_length;
view->file_version= 1;
view->calc_md5(md5);
view->md5.str= md5;
view->md5.length= 32;
can_be_merged= thd->lex->can_be_merged();
if (thd->lex->create_view_algorithm == VIEW_ALGORITHM_MERGE &&
!thd->lex->can_be_merged())
{
push_warning(thd, MYSQL_ERROR::WARN_LEVEL_WARN, ER_WARN_VIEW_MERGE,
ER(ER_WARN_VIEW_MERGE));
thd->lex->create_view_algorithm= VIEW_ALGORITHM_UNDEFINED;
}
view->algorithm= thd->lex->create_view_algorithm;
view->with_check= thd->lex->create_view_check;
if ((view->updatable_view= (can_be_merged &&
view->algorithm != VIEW_ALGORITHM_TMPTABLE)))
{
/* TODO: change here when we will support UNIONs */
for (TABLE_LIST *tbl= (TABLE_LIST *)thd->lex->select_lex.table_list.first;
tbl;
tbl= tbl->next_local)
{
if (tbl->view && !tbl->updatable_view)
{
view->updatable_view= 0;
break;
}
}
}
if (view->with_check != VIEW_CHECK_NONE &&
!view->updatable_view)
{
my_error(ER_VIEW_NONUPD_CHECK, MYF(0), view->db, view->real_name);
DBUG_RETURN(-1);
}
if (sql_create_definition_file(&dir, &file, view_file_type,
(gptr)view, view_parameters, 3))
{
DBUG_RETURN(thd->net.report_error? -1 : 1);
}
DBUG_RETURN(0);
}
/*
read VIEW .frm and create structures
SYNOPSIS
mysql_make_view()
parser - parser object;
table - TABLE_LIST structure for filling
RETURN
0 ok
1 error
*/
my_bool
mysql_make_view(File_parser *parser, TABLE_LIST *table)
{
DBUG_ENTER("mysql_make_view");
if (table->view)
{
DBUG_PRINT("info",
("VIEW %s.%s is already processed on previous PS/SP execution",
table->view_db.str, table->view_name.str));
DBUG_RETURN(0);
}
SELECT_LEX *end;
THD *thd= current_thd;
LEX *old_lex= thd->lex, *lex;
int res= 0;
/*
For now we assume that tables will not be changed during PS life (it
will be TRUE as far as we make new table cache).
*/
Item_arena *arena= thd->current_arena, backup;
if (arena->is_conventional())
arena= 0;
else
thd->set_n_backup_item_arena(arena, &backup);
/* init timestamp */
if (!table->timestamp.str)
table->timestamp.str= table->timestamp_buffer;
/*
TODO: when VIEWs will be stored in cache, table mem_root should
be used here
*/
if (parser->parse((gptr)table, &thd->mem_root, view_parameters,
required_view_parameters))
goto err;
/*
Save VIEW parameters, which will be wiped out by derived table
processing
*/
table->view_db.str= table->db;
table->view_db.length= table->db_length;
table->view_name.str= table->real_name;
table->view_name.length= table->real_name_length;
/*TODO: md5 test here and warning if it is differ */
/*
TODO: TABLE mem root should be used here when VIEW will be stored in
TABLE cache
now Lex placed in statement memory
*/
table->view= lex= thd->lex= (LEX*) new(&thd->mem_root) st_lex_local;
mysql_init_query(thd, (uchar*)table->query.str, table->query.length, TRUE);
lex->select_lex.select_number= ++thd->select_number;
old_lex->derived_tables|= DERIVED_VIEW;
{
ulong options= thd->options;
/* switch off modes which can prevent normal parsing of VIEW
- MODE_REAL_AS_FLOAT affect only CREATE TABLE parsing
+ MODE_PIPES_AS_CONCAT affect expression parsing
+ MODE_ANSI_QUOTES affect expression parsing
+ MODE_IGNORE_SPACE affect expression parsing
- MODE_NOT_USED not used :)
* MODE_ONLY_FULL_GROUP_BY affect execution
* MODE_NO_UNSIGNED_SUBTRACTION affect execution
- MODE_NO_DIR_IN_CREATE affect table creation only
- MODE_POSTGRESQL compounded from other modes
- MODE_ORACLE compounded from other modes
- MODE_MSSQL compounded from other modes
- MODE_DB2 compounded from other modes
- MODE_MAXDB affect only CREATE TABLE parsing
- MODE_NO_KEY_OPTIONS affect only SHOW
- MODE_NO_TABLE_OPTIONS affect only SHOW
- MODE_NO_FIELD_OPTIONS affect only SHOW
- MODE_MYSQL323 affect only SHOW
- MODE_MYSQL40 affect only SHOW
- MODE_ANSI compounded from other modes
(+ transaction mode)
? MODE_NO_AUTO_VALUE_ON_ZERO affect UPDATEs
+ MODE_NO_BACKSLASH_ESCAPES affect expression parsing
*/
thd->options&= ~(MODE_PIPES_AS_CONCAT | MODE_ANSI_QUOTES |
MODE_IGNORE_SPACE | MODE_NO_BACKSLASH_ESCAPES);
CHARSET_INFO *save_cs= thd->variables.character_set_client;
thd->variables.character_set_client= system_charset_info;
res= yyparse((void *)thd);
thd->variables.character_set_client= save_cs;
thd->options= options;
}
if (!res && !thd->is_fatal_error)
{
TABLE_LIST *top_view= (table->belong_to_view ?
table->belong_to_view :
table);
TABLE_LIST *view_tables= lex->query_tables;
TABLE_LIST *view_tables_tail= 0;
if (lex->spfuns.records)
{
/* move SP to main LEX */
sp_merge_funs(old_lex, lex);
/* open mysq.proc for functions which are not in cache */
if (old_lex->proc_table == 0 &&
(old_lex->proc_table=
(TABLE_LIST*)thd->calloc(sizeof(TABLE_LIST))) != 0)
{
TABLE_LIST *table= old_lex->proc_table;
table->db= (char*)"mysql";
table->db_length= 5;
table->real_name= table->alias= (char*)"proc";
table->real_name_length= 4;
table->cacheable_table= 1;
old_lex->add_to_query_tables(table);
}
}
/* cleanup LEX */
if (lex->spfuns.array.buffer)
hash_free(&lex->spfuns);
/*
mark to avoid temporary table using and put view reference and find
last view table
*/
for (TABLE_LIST *tbl= view_tables;
tbl;
tbl= (view_tables_tail= tbl)->next_global)
{
tbl->skip_temporary= 1;
tbl->belong_to_view= top_view;
}
/*
check rights to run commands (EXPLAIN SELECT & SHOW CREATE) which show
underlying tables
*/
if ((old_lex->sql_command == SQLCOM_SELECT && old_lex->describe))
{
if (check_table_access(thd, SELECT_ACL, view_tables, 1) &&
check_table_access(thd, SHOW_VIEW_ACL, table, 1))
{
my_error(ER_VIEW_NO_EXPLAIN, MYF(0));
goto err;
}
}
else if (old_lex->sql_command == SQLCOM_SHOW_CREATE)
{
if (check_table_access(thd, SHOW_VIEW_ACL, table, 0))
goto err;
}
/* move SQL_NO_CACHE & Co to whole query */
old_lex->safe_to_cache_query= (old_lex->safe_to_cache_query &&
lex->safe_to_cache_query);
/* move SQL_CACHE to whole query */
if (lex->select_lex.options & OPTION_TO_QUERY_CACHE)
old_lex->select_lex.options|= OPTION_TO_QUERY_CACHE;
/*
Put tables of VIEW after VIEW TABLE_LIST
NOTE: It is important for UPDATE/INSERT/DELETE checks to have this
tables just after VIEW instead of tail of list, to be able check that
table is unique. Also we store old next table for the same purpose.
*/
table->old_next= table->next_global;
if (view_tables)
{
if (table->next_global)
{
table->next_global->prev_global= &view_tables_tail->next_global;
view_tables_tail->next_global= table->old_next;
}
else
{
lex->query_tables_last= &view_tables_tail->next_global;
}
view_tables->prev_global= &table->next_global;
table->next_global= view_tables;
}
/*
check MERGE algorithm ability
- algorithm is not explicit TEMPORARY TABLE
- VIEW SELECT allow merging
- VIEW used in subquery or command support MERGE algorithm
*/
if (table->algorithm != VIEW_ALGORITHM_TMPTABLE &&
lex->can_be_merged() &&
(table->select_lex->master_unit() != &old_lex->unit ||
old_lex->can_use_merged()) &&
!old_lex->can_not_use_merged())
{
/*
TODO: support multi tables substitutions
*/
/* lex should contain at least one table */
DBUG_ASSERT(view_tables != 0);
table->effective_algorithm= VIEW_ALGORITHM_MERGE;
DBUG_PRINT("info", ("algorithm: MERGE"));
table->updatable= (table->updatable_view != 0);
table->effective_with_check= table->with_check;
table->ancestor= view_tables;
/*
next table should include SELECT_LEX under this table SELECT_LEX
TODO: here should be loop for multi tables substitution
*/
table->ancestor->select_lex= table->select_lex;
/*
move lock type (TODO: should we issue error in case of TMPTABLE
algorithm and non-read locking)?
*/
view_tables->lock_type= table->lock_type;
/* Store WHERE clause for post-processing in setup_ancestor */
table->where= lex->select_lex.where;
/*
Add subqueries units to SELECT in which we merging current view.
NOTE: we do not support UNION here, so we take only one select
*/
for (SELECT_LEX_UNIT *unit= lex->select_lex.first_inner_unit();
unit;
unit= unit->next_unit())
{
SELECT_LEX_NODE *save_slave= unit->slave;
unit->include_down(table->select_lex);
unit->slave= save_slave; // fix include_down initialisation
}
/*
This SELECT_LEX will be linked in global SELECT_LEX list
to make it processed by mysql_handle_derived(),
but it will not be included to SELECT_LEX tree, because it
will not be executed
*/
goto ok;
}
table->effective_algorithm= VIEW_ALGORITHM_TMPTABLE;
DBUG_PRINT("info", ("algorithm: TEMPORARY TABLE"));
lex->select_lex.linkage= DERIVED_TABLE_TYPE;
table->updatable= 0;
table->effective_with_check= VIEW_CHECK_NONE;
/* SELECT tree link */
lex->unit.include_down(table->select_lex);
lex->unit.slave= &lex->select_lex; // fix include_down initialisation
table->derived= &lex->unit;
}
else
goto err;
ok:
if (arena)
thd->restore_backup_item_arena(arena, &backup);
/* global SELECT list linking */
end= &lex->select_lex; // primary SELECT_LEX is always last
end->link_next= old_lex->all_selects_list;
old_lex->all_selects_list->link_prev= &end->link_next;
old_lex->all_selects_list= lex->all_selects_list;
lex->all_selects_list->link_prev=
(st_select_lex_node**)&old_lex->all_selects_list;
thd->lex= old_lex;
DBUG_RETURN(0);
err:
if (arena)
thd->restore_backup_item_arena(arena, &backup);
table->view= 0; // now it is not VIEW placeholder
thd->lex= old_lex;
DBUG_RETURN(1);
}
/*
drop view
SYNOPSIS
mysql_drop_view()
thd - thread handler
views - views to delete
drop_mode - cascade/check
RETURN VALUE
0 OK
-1 Error
1 Error and error message given
*/
int mysql_drop_view(THD *thd, TABLE_LIST *views, enum_drop_mode drop_mode)
{
DBUG_ENTER("mysql_drop_view");
char path[FN_REFLEN];
TABLE_LIST *view;
bool type= 0;
for (view= views; view; view= view->next_local)
{
strxnmov(path, FN_REFLEN, mysql_data_home, "/", view->db, "/",
view->real_name, reg_ext, NullS);
(void) unpack_filename(path, path);
VOID(pthread_mutex_lock(&LOCK_open));
if (access(path, F_OK) || (type= (mysql_frm_type(path) != FRMTYPE_VIEW)))
{
char name[FN_REFLEN];
my_snprintf(name, sizeof(name), "%s.%s", view->db, view->real_name);
if (thd->lex->drop_if_exists)
{
push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
ER_BAD_TABLE_ERROR, ER(ER_BAD_TABLE_ERROR),
name);
VOID(pthread_mutex_unlock(&LOCK_open));
continue;
}
if (type)
my_error(ER_WRONG_OBJECT, MYF(0), view->db, view->real_name, "VIEW");
else
my_error(ER_BAD_TABLE_ERROR, MYF(0), name);
goto err;
}
if (my_delete(path, MYF(MY_WME)))
goto err;
VOID(pthread_mutex_unlock(&LOCK_open));
}
send_ok(thd);
DBUG_RETURN(0);
err:
VOID(pthread_mutex_unlock(&LOCK_open));
DBUG_RETURN(-1);
}
/*
Check type of .frm if we are not going to parse it
SYNOPSIS
mysql_frm_type()
path path to file
RETURN
FRMTYPE_ERROR error
FRMTYPE_TABLE table
FRMTYPE_VIEW view
*/
frm_type_enum mysql_frm_type(char *path)
{
File file;
char header[10]; //"TYPE=VIEW\n" it is 10 characters
int length;
DBUG_ENTER("mysql_frm_type");
if ((file= my_open(path, O_RDONLY | O_SHARE, MYF(MY_WME))) < 0)
{
DBUG_RETURN(FRMTYPE_ERROR);
}
length= my_read(file, (byte*) header, 10, MYF(MY_WME));
my_close(file, MYF(MY_WME));
if (length == (int) MY_FILE_ERROR)
DBUG_RETURN(FRMTYPE_ERROR);
if (!strncmp(header, "TYPE=VIEW\n", 10))
DBUG_RETURN(FRMTYPE_VIEW);
DBUG_RETURN(FRMTYPE_TABLE); // Is probably a .frm table
}
/*
check of key (primary or unique) presence in updatable view
SYNOPSIS
check_key_in_view()
thd thread handler
view view for check with opened table
DESCRIPTION
If it is VIEW and query have LIMIT clause then check that undertlying
table of viey contain one of following:
1) primary key of underlying table
2) unique key underlying table with fields for which NULL value is
impossible
3) all fields of underlying table
RETURN
FALSE OK
TRUE view do not contain key or all fields
*/
bool check_key_in_view(THD *thd, TABLE_LIST *view)
{
TABLE *table;
Item **trans;
KEY *key_info, *key_info_end;
uint i, elements_in_view;
DBUG_ENTER("check_key_in_view");
/*
we do not support updatable UNIONs in VIW, so we can check just limit of
LEX::select_lex
*/
if (!view->view || thd->lex->sql_command == SQLCOM_INSERT ||
thd->lex->select_lex.select_limit == HA_POS_ERROR)
DBUG_RETURN(FALSE); /* it is normal table or query without LIMIT */
table= view->table;
trans= view->field_translation;
key_info_end= (key_info= table->key_info)+ table->keys;
elements_in_view= view->view->select_lex.item_list.elements;
DBUG_ASSERT(view->table != 0 && view->field_translation != 0);
/* Loop over all keys to see if a unique-not-null key is used */
for (;key_info != key_info_end ; key_info++)
{
if ((key_info->flags & (HA_NOSAME | HA_NULL_PART_KEY)) == HA_NOSAME)
{
KEY_PART_INFO *key_part= key_info->key_part;
KEY_PART_INFO *key_part_end= key_part + key_info->key_parts;
/* check that all key parts are used */
for (;;)
{
uint k;
for (k= 0; k < elements_in_view; k++)
{
Item_field *field;
if ((field= trans[k]->filed_for_view_update()) &&
field->field == key_part->field)
break;
}
if (k == elements_in_view)
break; // Key is not possible
if (++key_part == key_part_end)
DBUG_RETURN(FALSE); // Found usable key
}
}
}
DBUG_PRINT("info", ("checking if all fields of table are used"));
/* check all fields presence */
{
Field **field_ptr;
for (field_ptr= table->field; *field_ptr; field_ptr++)
{
for (i= 0; i < elements_in_view; i++)
{
Item_field *field;
if ((field= trans[i]->filed_for_view_update()) &&
field->field == *field_ptr)
break;
}
if (i == elements_in_view) // If field didn't exists
{
/*
Keys or all fields of underlaying tables are not foud => we have
to check variable updatable_views_with_limit to decide should we
issue an error or just a warning
*/
if (thd->variables.updatable_views_with_limit)
{
/* update allowed, but issue warning */
push_warning(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
ER_WARN_VIEW_WITHOUT_KEY, ER(ER_WARN_VIEW_WITHOUT_KEY));
DBUG_RETURN(FALSE);
}
/* prohibit update */
DBUG_RETURN(TRUE);
}
}
}
DBUG_RETURN(FALSE);
}
/*
insert fields from VIEW (MERGE algorithm) into given list
SYNOPSIS
insert_view_fields()
list list for insertion
view view for processing
*/
void insert_view_fields(List<Item> *list, TABLE_LIST *view)
{
uint elements_in_view= view->view->select_lex.item_list.elements;
Item **trans;
DBUG_ENTER("insert_view_fields");
if (!(trans= view->field_translation))
DBUG_VOID_RETURN;
for (uint i= 0; i < elements_in_view; i++)
{
Item_field *fld;
if ((fld= trans[i]->filed_for_view_update()))
list->push_back(fld);
}
DBUG_VOID_RETURN;
}
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