summaryrefslogtreecommitdiff
path: root/sql/table.h
blob: f0190353328ea32542cee029586d69e9dc350348 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult 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 */


/* Structs that defines the TABLE */

class Item;				/* Needed by ORDER */
class Item_subselect;
class GRANT_TABLE;
class st_select_lex_unit;
class st_select_lex;
class COND_EQUAL;
class Security_context;

/* Order clause list element */

typedef struct st_order {
  struct st_order *next;
  Item	 **item;			/* Point at item in select fields */
  Item	 *item_ptr;			/* Storage for initial item */
  Item   **item_copy;			/* For SPs; the original item ptr */
  int    counter;                       /* position in SELECT list, correct
                                           only if counter_used is true*/
  bool	 asc;				/* true if ascending */
  bool	 free_me;			/* true if item isn't shared  */
  bool	 in_field_list;			/* true if in select field list */
  bool   counter_used;                  /* parameter was counter of columns */
  Field  *field;			/* If tmp-table group */
  char	 *buff;				/* If tmp-table group */
  table_map used, depend_map;
} ORDER;

typedef struct st_grant_info
{
  GRANT_TABLE *grant_table;
  uint version;
  ulong privilege;
  ulong want_privilege;
  /*
    Stores the requested access acl of top level tables list. Is used to
    check access rights to the underlying tables of a view.
  */
  ulong orig_want_privilege;
} GRANT_INFO;

enum tmp_table_type {NO_TMP_TABLE=0, TMP_TABLE=1, TRANSACTIONAL_TMP_TABLE=2,
                     SYSTEM_TMP_TABLE=3};

enum frm_type_enum
{
  FRMTYPE_ERROR= 0,
  FRMTYPE_TABLE,
  FRMTYPE_VIEW
};

typedef struct st_filesort_info
{
  IO_CACHE *io_cache;           /* If sorted through filebyte                */
  uchar   **sort_keys;          /* Buffer for sorting keys                   */
  byte     *buffpek;            /* Buffer for buffpek structures             */
  uint      buffpek_len;        /* Max number of buffpeks in the buffer      */
  byte     *addon_buf;          /* Pointer to a buffer if sorted with fields */
  uint      addon_length;       /* Length of the buffer                      */
  struct st_sort_addon_field *addon_field;     /* Pointer to the fields info */
  void    (*unpack)(struct st_sort_addon_field *, byte *); /* To unpack back */
  byte     *record_pointers;    /* If sorted in memory                       */
  ha_rows   found_records;      /* How many records in sort                  */
} FILESORT_INFO;


/*
  Values in this enum are used to indicate how a tables TIMESTAMP field
  should be treated. It can be set to the current timestamp on insert or
  update or both.
  WARNING: The values are used for bit operations. If you change the
  enum, you must keep the bitwise relation of the values. For example:
  (int) TIMESTAMP_AUTO_SET_ON_BOTH must be equal to
  (int) TIMESTAMP_AUTO_SET_ON_INSERT | (int) TIMESTAMP_AUTO_SET_ON_UPDATE.
  We use an enum here so that the debugger can display the value names.
*/
enum timestamp_auto_set_type
{
  TIMESTAMP_NO_AUTO_SET= 0, TIMESTAMP_AUTO_SET_ON_INSERT= 1,
  TIMESTAMP_AUTO_SET_ON_UPDATE= 2, TIMESTAMP_AUTO_SET_ON_BOTH= 3
};
#define clear_timestamp_auto_bits(_target_, _bits_) \
  (_target_)= (enum timestamp_auto_set_type)((int)(_target_) & ~(int)(_bits_))

class Field_timestamp;
class Field_blob;
class Table_triggers_list;

/*
  This structure is shared between different table objects. There is one
  instance of table share per one table in the database.
*/

typedef struct st_table_share
{
  /* hash of field names (contains pointers to elements of field array) */
  HASH	name_hash;			/* hash of field names */
  MEM_ROOT mem_root;
  TYPELIB keynames;			/* Pointers to keynames */
  TYPELIB fieldnames;			/* Pointer to fieldnames */
  TYPELIB *intervals;			/* pointer to interval info */
#ifdef NOT_YET
  pthread_mutex_t mutex;                /* For locking the share  */
  pthread_cond_t cond;			/* To signal that share is ready */
  struct st_table *open_tables;		/* link to open tables */
  struct st_table *used_next,		/* Link to used tables */
		 **used_prev;
  /* The following is copied to each TABLE on OPEN */
  Field **field;
  KEY  *key_info;			/* data of keys in database */
#endif
  uint	*blob_field;			/* Index to blobs in Field arrray*/
  byte	*default_values;		/* row with default values */
  LEX_STRING comment;			/* Comment about table */
  CHARSET_INFO *table_charset;		/* Default charset of string fields */

  /* A pair "database_name\0table_name\0", widely used as simply a db name */
  char	*table_cache_key;
  const char *db;                       /* Pointer to db */
  const char *table_name;               /* Table name (for open) */
  const char *path;                     /* Path to .frm file (from datadir) */
  LEX_STRING connect_string;
  key_map keys_in_use;                  /* Keys in use for table */
  key_map keys_for_keyread;
  ulong   avg_row_length;		/* create information */
  ulong   raid_chunksize;
  ulong   version, flush_version, mysql_version;
  ulong   timestamp_offset;		/* Set to offset+1 of record */
  ulong   reclength;			/* Recordlength */

  ha_rows min_rows, max_rows;		/* create information */
  enum db_type db_type;			/* table_type for handler */
  enum row_type row_type;		/* How rows are stored */
  enum tmp_table_type tmp_table;

  uint blob_ptr_size;			/* 4 or 8 */
  uint null_bytes, last_null_bit_pos;
  uint key_length;			/* Length of table_cache_key */
  uint fields;				/* Number of fields */
  uint rec_buff_length;                 /* Size of table->record[] buffer */
  uint keys, key_parts;
  uint max_key_length, max_unique_length, total_key_length;
  uint uniques;                         /* Number of UNIQUE index */
  uint null_fields;			/* number of null fields */
  uint blob_fields;			/* number of blob fields */
  uint varchar_fields;                  /* number of varchar fields */
  uint db_create_options;		/* Create options from database */
  uint db_options_in_use;		/* Options in use */
  uint db_record_offset;		/* if HA_REC_IN_SEQ */
  uint raid_type, raid_chunks;
  uint open_count;			/* Number of tables in open list */
  /* Index of auto-updated TIMESTAMP field in field array */
  uint primary_key;
  uint timestamp_field_offset;
  uint next_number_index;
  uint next_number_key_offset;
  uchar	  frm_version;
  my_bool system;			/* Set if system record */
  my_bool crypted;                      /* If .frm file is crypted */
  my_bool db_low_byte_first;		/* Portable row format */
  my_bool crashed;
  my_bool is_view;
  my_bool name_lock, replace_with_name_lock;
  /*
    TRUE if this is a system table like 'mysql.proc', which we want to be
    able to open and lock even when we already have some tables open and
    locked. To avoid deadlocks we have to put certain restrictions on
    locking of this table for writing. FALSE - otherwise.
  */
  my_bool system_table;
} TABLE_SHARE;


/* Information for one open table */

struct st_table {
  st_table() {}                               /* Remove gcc warning */

  TABLE_SHARE	*s;
  handler	*file;
#ifdef NOT_YET
  struct st_table *used_next, **used_prev;	/* Link to used tables */
  struct st_table *open_next, **open_prev;	/* Link to open tables */
#endif
  struct st_table *next, *prev;

  THD	*in_use;                        /* Which thread uses this */
  Field **field;			/* Pointer to fields */

  byte *record[2];			/* Pointer to records */
  byte *insert_values;                  /* used by INSERT ... UPDATE */
  key_map quick_keys, used_keys, keys_in_use_for_query;
  KEY  *key_info;			/* data of keys in database */

  Field *next_number_field,		/* Set if next_number is activated */
	*found_next_number_field,	/* Set on open */
        *rowid_field;
  Field_timestamp *timestamp_field;

  /* Table's triggers, 0 if there are no of them */
  Table_triggers_list *triggers;
  struct st_table_list *pos_in_table_list;/* Element referring to this table */
  ORDER		*group;
  const char	*alias;            	  /* alias or table name */
  uchar		*null_flags;
  query_id_t	query_id;

  ha_rows	quick_rows[MAX_KEY];
  key_part_map  const_key_parts[MAX_KEY];
  uint		quick_key_parts[MAX_KEY];
  uint		quick_n_ranges[MAX_KEY];

  /*
    If this table has TIMESTAMP field with auto-set property (pointed by
    timestamp_field member) then this variable indicates during which
    operations (insert only/on update/in both cases) we should set this
    field to current timestamp. If there are no such field in this table
    or we should not automatically set its value during execution of current
    statement then the variable contains TIMESTAMP_NO_AUTO_SET (i.e. 0).

    Value of this variable is set for each statement in open_table() and
    if needed cleared later in statement processing code (see mysql_update()
    as example).
  */
  timestamp_auto_set_type timestamp_field_type;
  table_map	map;                    /* ID bit of table (1,2,4,8,16...) */

  uint          lock_position;          /* Position in MYSQL_LOCK.table */
  uint          lock_data_start;        /* Start pos. in MYSQL_LOCK.locks */
  uint          lock_count;             /* Number of locks */
  uint		tablenr,used_fields;
  uint          temp_pool_slot;		/* Used by intern temp tables */
  uint		status;                 /* What's in record[0] */
  uint		db_stat;		/* mode of file as in handler.h */
  /* number of select if it is derived table */
  uint          derived_select_number;
  int		current_lock;           /* Type of lock on table */
  my_bool copy_blobs;			/* copy_blobs when storing */

  /*
    0 or JOIN_TYPE_{LEFT|RIGHT}. Currently this is only compared to 0.
    If maybe_null !=0, this table is inner w.r.t. some outer join operation,
    and null_row may be true.
  */
  uint maybe_null;
  /*
    If true, the current table row is considered to have all columns set to 
    NULL, including columns declared as "not null" (see maybe_null).
  */
  my_bool null_row;
  my_bool force_index;
  my_bool distinct,const_table,no_rows;
  my_bool key_read, no_keyread;
  my_bool locked_by_flush;
  my_bool locked_by_name;
  my_bool fulltext_searched;
  my_bool no_cache;
  /* To signal that we should reset query_id for tables and cols */
  my_bool clear_query_id;
  my_bool auto_increment_field_not_null;
  my_bool insert_or_update;             /* Can be used by the handler */
  my_bool alias_name_used;		/* true if table_name is alias */

  REGINFO reginfo;			/* field connections */
  MEM_ROOT mem_root;
  GRANT_INFO grant;
  FILESORT_INFO sort;
  TABLE_SHARE share_not_to_be_used;     /* To be deleted when true shares */

  bool fill_item_list(List<Item> *item_list) const;
  void reset_item_list(List<Item> *item_list) const;
};


typedef struct st_foreign_key_info
{
  LEX_STRING *forein_id;
  LEX_STRING *referenced_db;
  LEX_STRING *referenced_table;
  LEX_STRING *constraint_method;
  List<LEX_STRING> foreign_fields;
  List<LEX_STRING> referenced_fields;
} FOREIGN_KEY_INFO;


enum enum_schema_tables
{
  SCH_CHARSETS= 0,
  SCH_COLLATIONS,
  SCH_COLLATION_CHARACTER_SET_APPLICABILITY,
  SCH_COLUMNS,
  SCH_COLUMN_PRIVILEGES,
  SCH_KEY_COLUMN_USAGE,
  SCH_OPEN_TABLES,
  SCH_PROCEDURES,
  SCH_SCHEMATA,
  SCH_SCHEMA_PRIVILEGES,
  SCH_STATISTICS,
  SCH_STATUS,
  SCH_TABLES,
  SCH_TABLE_CONSTRAINTS,
  SCH_TABLE_NAMES,
  SCH_TABLE_PRIVILEGES,
  SCH_TRIGGERS,
  SCH_USER_PRIVILEGES,
  SCH_VARIABLES,
  SCH_VIEWS
};


typedef struct st_field_info
{
  const char* field_name;
  uint field_length;
  enum enum_field_types field_type;
  int value;
  bool maybe_null;
  const char* old_name;
} ST_FIELD_INFO;


struct st_table_list;
typedef class Item COND;

typedef struct st_schema_table
{
  const char* table_name;
  ST_FIELD_INFO *fields_info;
  /* Create information_schema table */
  TABLE *(*create_table)  (THD *thd, struct st_table_list *table_list);
  /* Fill table with data */
  int (*fill_table) (THD *thd, struct st_table_list *tables, COND *cond);
  /* Handle fileds for old SHOW */
  int (*old_format) (THD *thd, struct st_schema_table *schema_table);
  int (*process_table) (THD *thd, struct st_table_list *tables,
                        TABLE *table, bool res, const char *base_name,
                        const char *file_name);
  int idx_field1, idx_field2; 
  bool hidden;
} ST_SCHEMA_TABLE;


#define JOIN_TYPE_LEFT	1
#define JOIN_TYPE_RIGHT	2

#define VIEW_ALGORITHM_UNDEFINED        0
#define VIEW_ALGORITHM_TMPTABLE         1
#define VIEW_ALGORITHM_MERGE            2

#define VIEW_SUID_INVOKER               0
#define VIEW_SUID_DEFINER               1
#define VIEW_SUID_DEFAULT               2

/* view WITH CHECK OPTION parameter options */
#define VIEW_CHECK_NONE       0
#define VIEW_CHECK_LOCAL      1
#define VIEW_CHECK_CASCADED   2

/* result of view WITH CHECK OPTION parameter check */
#define VIEW_CHECK_OK         0
#define VIEW_CHECK_ERROR      1
#define VIEW_CHECK_SKIP       2

struct st_lex;
class select_union;
class TMP_TABLE_PARAM;

Item *create_view_field(THD *thd, st_table_list *view, Item **field_ref,
                        const char *name);

struct Field_translator
{
  Item *item;
  const char *name;
};


/*
  Column reference of a NATURAL/USING join. Since column references in
  joins can be both from views and stored tables, may point to either a
  Field (for tables), or a Field_translator (for views).
*/

class Natural_join_column: public Sql_alloc
{
public:
  Field_translator *view_field;  /* Column reference of merge view. */
  Field            *table_field; /* Column reference of table or temp view. */
  st_table_list *table_ref; /* Original base table/view reference. */
  /*
    True if a common join column of two NATURAL/USING join operands. Notice
    that when we have a hierarchy of nested NATURAL/USING joins, a column can
    be common at some level of nesting but it may not be common at higher
    levels of nesting. Thus this flag may change depending on at which level
    we are looking at some column.
  */
  bool is_common;
public:
  Natural_join_column(Field_translator *field_param, st_table_list *tab);
  Natural_join_column(Field *field_param, st_table_list *tab);
  const char *name();
  Item *create_item(THD *thd);
  Field *field();
  const char *table_name();
  const char *db_name();
  GRANT_INFO *grant();
};


/*
  Table reference in the FROM clause.

  These table references can be of several types that correspond to
  different SQL elements. Below we list all types of TABLE_LISTs with
  the necessary conditions to determine when a TABLE_LIST instance
  belongs to a certain type.

  1) table (TABLE_LIST::view == NULL)
     - base table
       (TABLE_LIST::derived == NULL)
     - subquery - TABLE_LIST::table is a temp table
       (TABLE_LIST::derived != NULL)
     - information schema table
       (TABLE_LIST::schema_table != NULL)
       NOTICE: for schema tables TABLE_LIST::field_translation may be != NULL
  2) view (TABLE_LIST::view != NULL)
     - merge    (TABLE_LIST::effective_algorithm == VIEW_ALGORITHM_MERGE)
           also (TABLE_LIST::field_translation != NULL)
     - tmptable (TABLE_LIST::effective_algorithm == VIEW_ALGORITHM_TMPTABLE)
           also (TABLE_LIST::field_translation == NULL)
  3) nested table reference (TABLE_LIST::nested_join != NULL)
     - table sequence - e.g. (t1, t2, t3)
       TODO: how to distinguish from a JOIN?
     - general JOIN
       TODO: how to distinguish from a table sequence?
     - NATURAL JOIN
       (TABLE_LIST::natural_join != NULL)
       - JOIN ... USING
         (TABLE_LIST::join_using_fields != NULL)
*/

typedef struct st_table_list
{
  st_table_list() {}                          /* Remove gcc warning */
  /*
    List of tables local to a subquery (used by SQL_LIST). Considers
    views as leaves (unlike 'next_leaf' below). Created at parse time
    in st_select_lex::add_table_to_list() -> table_list.link_in_list().
  */
  struct st_table_list *next_local;
  /* link in a global list of all queries tables */
  struct st_table_list *next_global, **prev_global;
  char		*db, *alias, *table_name, *schema_table_name;
  char          *option;                /* Used by cache index  */
  Item		*on_expr;		/* Used with outer join */
  /*
    The structure of ON expression presented in the member above
    can be changed during certain optimizations. This member
    contains a snapshot of AND-OR structure of the ON expression
    made after permanent transformations of the parse tree, and is
    used to restore ON clause before every reexecution of a prepared
    statement or stored procedure.
  */
  Item          *prep_on_expr;
  COND_EQUAL    *cond_equal;            /* Used with outer join */
  /*
    During parsing - left operand of NATURAL/USING join where 'this' is
    the right operand. After parsing (this->natural_join == this) iff
    'this' represents a NATURAL or USING join operation. Thus after
    parsing 'this' is a NATURAL/USING join iff (natural_join != NULL).
  */
  struct st_table_list *natural_join;
  /*
    True if 'this' represents a nested join that is a NATURAL JOIN.
    For one of the operands of 'this', the member 'natural_join' points
    to the other operand of 'this'.
  */
  bool is_natural_join;
  /* Field names in a USING clause for JOIN ... USING. */
  List<String> *join_using_fields;
  /*
    Explicitly store the result columns of either a NATURAL/USING join or
    an operand of such a join.
  */
  List<Natural_join_column> *join_columns;
  /* TRUE if join_columns contains all columns of this table reference. */
  bool is_join_columns_complete;

  /*
    List of nodes in a nested join tree, that should be considered as
    leaves with respect to name resolution. The leaves are: views,
    top-most nodes representing NATURAL/USING joins, subqueries, and
    base tables. All of these TABLE_LIST instances contain a
    materialized list of columns. The list is local to a subquery.
  */
  struct st_table_list *next_name_resolution_table;
  /* Index names in a "... JOIN ... USE/IGNORE INDEX ..." clause. */
  List<String> *use_index, *ignore_index;
  TABLE        *table;                   /* opened table */
  /*
    select_result for derived table to pass it from table creation to table
    filling procedure
  */
  select_union  *derived_result;
  /*
    Reference from aux_tables to local list entry of main select of
    multi-delete statement:
    delete t1 from t2,t1 where t1.a<'B' and t2.b=t1.b;
    here it will be reference of first occurrence of t1 to second (as you
    can see this lists can't be merged)
  */
  st_table_list	*correspondent_table;
  st_select_lex_unit *derived;		/* SELECT_LEX_UNIT of derived table */
  ST_SCHEMA_TABLE *schema_table;        /* Information_schema table */
  st_select_lex	*schema_select_lex;
  bool is_schema_table_processed;
  /*
    True when the view field translation table is used to convert
    schema table fields for backwards compatibility with SHOW command.
  */
  bool schema_table_reformed;
  TMP_TABLE_PARAM *schema_table_param;
  /* link to select_lex where this table was used */
  st_select_lex	*select_lex;
  st_lex	*view;			/* link on VIEW lex for merging */
  Field_translator *field_translation;	/* array of VIEW fields */
  /* pointer to element after last one in translation table above */
  Field_translator *field_translation_end;
  /*
    List (based on next_local) of underlying tables of this view. I.e. it
    does not include the tables of subqueries used in the view. Is set only
    for merged views.
  */
  st_table_list	*merge_underlying_list;
  /*
    - 0 for base tables
    - in case of the view it is the list of all (not only underlying
    tables but also used in subquery ones) tables of the view.
  */
  List<st_table_list> *view_tables;
  /* most upper view this table belongs to */
  st_table_list	*belong_to_view;
  /*
    The view directly referencing this table
    (non-zero only for merged underlying tables of a view).
  */
  st_table_list	*referencing_view;
  /*
    Security  context (non-zero only for tables which belong
    to view with SQL SECURITY DEFINER)
  */
  Security_context *security_ctx;
  /*
    This view security context (non-zero only for views with
    SQL SECURITY DEFINER)
  */
  Security_context *view_sctx;
  /*
    List of all base tables local to a subquery including all view
    tables. Unlike 'next_local', this in this list views are *not*
    leaves. Created in setup_tables() -> make_leaves_list().
  */
  bool allowed_show;
  st_table_list	*next_leaf;
  Item          *where;                 /* VIEW WHERE clause condition */
  Item          *check_option;          /* WITH CHECK OPTION condition */
  LEX_STRING	query;			/* text of (CRETE/SELECT) statement */
  LEX_STRING	md5;			/* md5 of query text */
  LEX_STRING	source;			/* source of CREATE VIEW */
  LEX_STRING	view_db;		/* saved view database */
  LEX_STRING	view_name;		/* saved view name */
  LEX_STRING	timestamp;		/* GMT time stamp of last operation */
  st_lex_user   definer;                /* definer of view */
  ulonglong	file_version;		/* version of file's field set */
  ulonglong     updatable_view;         /* VIEW can be updated */
  ulonglong	revision;		/* revision control number */
  ulonglong	algorithm;		/* 0 any, 1 tmp tables , 2 merging */
  ulonglong     view_suid;              /* view is suid (TRUE dy default) */
  ulonglong     with_check;             /* WITH CHECK OPTION */
  /*
    effective value of WITH CHECK OPTION (differ for temporary table
    algorithm)
  */
  uint8         effective_with_check;
  uint8         effective_algorithm;    /* which algorithm was really used */
  GRANT_INFO	grant;
  /* data need by some engines in query cache*/
  ulonglong     engine_data;
  /* call back function for asking handler about caching in query cache */
  qc_engine_callback callback_func;
  thr_lock_type lock_type;
  uint		outer_join;		/* Which join type */
  uint		shared;			/* Used in multi-upd */
  uint          db_length;
  uint32        table_name_length;
  bool          updatable;		/* VIEW/TABLE can be updated now */
  bool		straight;		/* optimize with prev table */
  bool          updating;               /* for replicate-do/ignore table */
  bool		force_index;		/* prefer index over table scan */
  bool          ignore_leaves;          /* preload only non-leaf nodes */
  table_map     dep_tables;             /* tables the table depends on      */
  table_map     on_expr_dep_tables;     /* tables on expression depends on  */
  struct st_nested_join *nested_join;   /* if the element is a nested join  */
  st_table_list *embedding;             /* nested join containing the table */
  List<struct st_table_list> *join_list;/* join list the table belongs to   */
  bool		cacheable_table;	/* stop PS caching */
  /* used in multi-upd/views privilege check */
  bool		table_in_first_from_clause;
  bool		skip_temporary;		/* this table shouldn't be temporary */
  /* TRUE if this merged view contain auto_increment field */
  bool          contain_auto_increment;
  bool          multitable_view;        /* TRUE iff this is multitable view */
  bool          compact_view_format;    /* Use compact format for SHOW CREATE VIEW */
  /* view where processed */
  bool          where_processed;
  /* FRMTYPE_ERROR if any type is acceptable */
  enum frm_type_enum required_type;
  char		timestamp_buffer[20];	/* buffer for timestamp (19+1) */
  /*
    This TABLE_LIST object is just placeholder for prelocking, it will be
    used for implicit LOCK TABLES only and won't be used in real statement.
  */
  bool          prelocking_placeholder;

  void calc_md5(char *buffer);
  void set_underlying_merge();
  int view_check_option(THD *thd, bool ignore_failure);
  bool setup_underlying(THD *thd);
  void cleanup_items();
  bool placeholder() {return derived || view; }
  void print(THD *thd, String *str);
  bool check_single_table(st_table_list **table, table_map map,
                          st_table_list *view);
  bool set_insert_values(MEM_ROOT *mem_root);
  void hide_view_error(THD *thd);
  st_table_list *find_underlying_table(TABLE *table);
  st_table_list *first_leaf_for_name_resolution();
  st_table_list *last_leaf_for_name_resolution();
  bool is_leaf_for_name_resolution();
  inline st_table_list *top_table()
    { return belong_to_view ? belong_to_view : this; }
  inline bool prepare_check_option(THD *thd)
  {
    bool res= FALSE;
    if (effective_with_check)
      res= prep_check_option(thd, effective_with_check);
    return res;
  }
  inline bool prepare_where(THD *thd, Item **conds,
                            bool no_where_clause)
  {
    if (effective_algorithm == VIEW_ALGORITHM_MERGE)
      return prep_where(thd, conds, no_where_clause);
    return FALSE;
  }

  void register_want_access(ulong want_access);
  bool prepare_security(THD *thd);
#ifndef NO_EMBEDDED_ACCESS_CHECKS
  Security_context *find_view_security_context(THD *thd);
  bool prepare_view_securety_context(THD *thd);
#endif
  /*
    Cleanup for re-execution in a prepared statement or a stored
    procedure.
  */
  void reinit_before_use(THD *thd);
  Item_subselect *containing_subselect();

private:
  bool prep_check_option(THD *thd, uint8 check_opt_type);
  bool prep_where(THD *thd, Item **conds, bool no_where_clause);
  /*
    Cleanup for re-execution in a prepared statement or a stored
    procedure.
  */
} TABLE_LIST;

class Item;

/*
  Iterator over the fields of a generic table reference.
*/

class Field_iterator: public Sql_alloc
{
public:
  Field_iterator() {}                         /* Remove gcc warning */
  virtual ~Field_iterator() {}
  virtual void set(TABLE_LIST *)= 0;
  virtual void next()= 0;
  virtual bool end_of_fields()= 0;              /* Return 1 at end of list */
  virtual const char *name()= 0;
  virtual Item *create_item(THD *)= 0;
  virtual Field *field()= 0;
};


/* 
  Iterator over the fields of a base table, view with temporary
  table, or subquery.
*/

class Field_iterator_table: public Field_iterator
{
  Field **ptr;
public:
  Field_iterator_table() :ptr(0) {}
  void set(TABLE_LIST *table) { ptr= table->table->field; }
  void set_table(TABLE *table) { ptr= table->field; }
  void next() { ptr++; }
  bool end_of_fields() { return *ptr == 0; }
  const char *name();
  Item *create_item(THD *thd);
  Field *field() { return *ptr; }
};


/* Iterator over the fields of a merge view. */

class Field_iterator_view: public Field_iterator
{
  Field_translator *ptr, *array_end;
  TABLE_LIST *view;
public:
  Field_iterator_view() :ptr(0), array_end(0) {}
  void set(TABLE_LIST *table);
  void next() { ptr++; }
  bool end_of_fields() { return ptr == array_end; }
  const char *name();
  Item *create_item(THD *thd);
  Item **item_ptr() {return &ptr->item; }
  Field *field() { return 0; }
  inline Item *item() { return ptr->item; }
  Field_translator *field_translator() { return ptr; }
};


/*
  Field_iterator interface to the list of materialized fields of a
  NATURAL/USING join.
*/

class Field_iterator_natural_join: public Field_iterator
{
  List_iterator_fast<Natural_join_column> column_ref_it;
  Natural_join_column *cur_column_ref;
public:
  Field_iterator_natural_join() :cur_column_ref(NULL) {}
  ~Field_iterator_natural_join() {}
  void set(TABLE_LIST *table);
  void next();
  bool end_of_fields() { return !cur_column_ref; }
  const char *name() { return cur_column_ref->name(); }
  Item *create_item(THD *thd) { return cur_column_ref->create_item(thd); }
  Field *field() { return cur_column_ref->field(); }
  Natural_join_column *column_ref() { return cur_column_ref; }
};


/*
  Generic iterator over the fields of an arbitrary table reference.

  DESCRIPTION
    This class unifies the various ways of iterating over the columns
    of a table reference depending on the type of SQL entity it
    represents. If such an entity represents a nested table reference,
    this iterator encapsulates the iteration over the columns of the
    members of the table reference.

  IMPLEMENTATION
    The implementation assumes that all underlying NATURAL/USING table
    references already contain their result columns and are linked into
    the list TABLE_LIST::next_name_resolution_table.
*/

class Field_iterator_table_ref: public Field_iterator
{
  TABLE_LIST *table_ref, *first_leaf, *last_leaf;
  Field_iterator_table        table_field_it;
  Field_iterator_view         view_field_it;
  Field_iterator_natural_join natural_join_it;
  Field_iterator *field_it;
  void set_field_iterator();
public:
  Field_iterator_table_ref() :field_it(NULL) {}
  void set(TABLE_LIST *table);
  void next();
  bool end_of_fields()
  { return (table_ref == last_leaf && field_it->end_of_fields()); }
  const char *name() { return field_it->name(); }
  const char *table_name();
  const char *db_name();
  GRANT_INFO *grant();
  Item *create_item(THD *thd) { return field_it->create_item(thd); }
  Field *field() { return field_it->field(); }
  Natural_join_column *get_or_create_column_ref(TABLE_LIST *parent_table_ref);
  Natural_join_column *get_natural_column_ref();
};


typedef struct st_nested_join
{
  List<TABLE_LIST>  join_list;       /* list of elements in the nested join */
  table_map         used_tables;     /* bitmap of tables in the nested join */
  table_map         not_null_tables; /* tables that rejects nulls           */
  struct st_join_table *first_nested;/* the first nested table in the plan  */
  /* 
    Used to count tables in the nested join in 2 isolated places:
    1. In make_outerjoin_info(). 
    2. check_interleaving_with_nj/restore_prev_nj_state (these are called
       by the join optimizer. 
    Before each use the counters are zeroed by reset_nj_counters.
  */
  uint              counter;
  nested_join_map   nj_map;          /* Bit used to identify this nested join*/
} NESTED_JOIN;


typedef struct st_changed_table_list
{
  struct	st_changed_table_list *next;
  char		*key;
  uint32        key_length;
} CHANGED_TABLE_LIST;


typedef struct st_open_table_list{
  struct st_open_table_list *next;
  char	*db,*table;
  uint32 in_use,locked;
} OPEN_TABLE_LIST;