summaryrefslogtreecommitdiff
path: root/sql/key.cc
blob: fa09a0a6d4493170eebd7b02b2634b1f17a1b8fd (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
/* 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 */


/* Functions to handle keys and fields in forms */

#include "mysql_priv.h"

	/*
	** Search after with key field is. If no key starts with field test
	** if field is part of some key.
	**
	** returns number of key. keylength is set to length of key before
	** (not including) field
	** Used when calculating key for NEXT_NUMBER
	*/

int find_ref_key(TABLE *table,Field *field, uint *key_length)
{
  reg2 int i;
  reg3 KEY *key_info;
  uint fieldpos;

  fieldpos=    field->offset();

	/* Test if some key starts as fieldpos */

  for (i=0, key_info=table->key_info ; i < (int) table->keys ; i++, key_info++)
  {
    if (key_info->key_part[0].offset == fieldpos)
    {						/* Found key. Calc keylength */
      *key_length=0;
      return(i);			/* Use this key */
    }
  }
	/* Test if some key contains fieldpos */

  for (i=0, key_info=table->key_info ; i < (int) table->keys ; i++, key_info++)
  {
    uint j;
    KEY_PART_INFO *key_part;
    *key_length=0;
    for (j=0, key_part=key_info->key_part ;
	 j < key_info->key_parts ;
	 j++, key_part++)
    {
      if (key_part->offset == fieldpos)
	return(i);			/* Use this key */
      *key_length+=key_part->store_length;
    }
  }
  return(-1);					/* No key is ok */
}


	/* Copy a key from record to some buffer */
	/* if length == 0 then copy hole key */

void key_copy(byte *key,TABLE *table,uint idx,uint key_length)
{
  uint length;
  KEY *key_info=table->key_info+idx;
  KEY_PART_INFO *key_part;

  if (key_length == 0)
    key_length=key_info->key_length;
  for (key_part=key_info->key_part;
       (int) key_length > 0 ;
       key_part++)
  {
    if (key_part->null_bit)
    {
      *key++= test(table->record[0][key_part->null_offset] &
		   key_part->null_bit);
      key_length--;
    }
    if (key_part->key_part_flag & HA_BLOB_PART)
    {
      char *pos;
      ulong blob_length=((Field_blob*) key_part->field)->get_length();
      key_length-=2;
      ((Field_blob*) key_part->field)->get_ptr(&pos);
      length=min(key_length,key_part->length);
      set_if_smaller(blob_length,length);
      int2store(key,(uint) blob_length);
      key+=2;					// Skip length info
      memcpy(key,pos,blob_length);
    }
    else
    {
      length=min(key_length,key_part->length);
      memcpy(key,table->record[0]+key_part->offset,(size_t) length);
    }
    key+=length;
    key_length-=length;
  }
} /* key_copy */


	/* restore a key from some buffer to record */

void key_restore(TABLE *table,byte *key,uint idx,uint key_length)
{
  uint length;
  KEY *key_info=table->key_info+idx;
  KEY_PART_INFO *key_part;

  if (key_length == 0)
  {
    if (idx == (uint) -1)
      return;
    key_length=key_info->key_length;
  }
  for (key_part=key_info->key_part;
       (int) key_length > 0 ;
       key_part++)
  {
    if (key_part->null_bit)
    {
      if (*key++)
	table->record[0][key_part->null_offset]|= key_part->null_bit;
      else
	table->record[0][key_part->null_offset]&= ~key_part->null_bit;
      key_length--;
    }
    if (key_part->key_part_flag & HA_BLOB_PART)
    {
      uint blob_length=uint2korr(key);
      key+=2;
      key_length-=2;
      ((Field_blob*) key_part->field)->set_ptr((ulong) blob_length,
					       (char*) key);
      length=key_part->length;
    }
    else
    {
      length=min(key_length,key_part->length);
      memcpy(table->record[0]+key_part->offset,key,(size_t) length);
    }
    key+=length;
    key_length-=length;
  }
} /* key_restore */


	/* Compare if a key has changed */

int key_cmp(TABLE *table,const byte *key,uint idx,uint key_length)
{
  uint length;
  KEY_PART_INFO *key_part;

  for (key_part=table->key_info[idx].key_part;
       (int) key_length > 0;
       key_part++, key+=length, key_length-=length)
  {
    if (key_part->null_bit)
    {
      key_length--;
      if (*key != test(table->record[0][key_part->null_offset] & 
		       key_part->null_bit))
	return 1;
      if (*key)
      {
	length=key_part->store_length;
	continue;
      }
      key++;
    }
    if (key_part->key_part_flag & (HA_BLOB_PART | HA_VAR_LENGTH))
    {
      if (key_part->field->key_cmp(key, key_part->length+2))
	return 1;
      length=key_part->length+2;
    }
    else
    {
      length=min(key_length,key_part->length);
      if (!(key_part->key_type & (FIELDFLAG_NUMBER+FIELDFLAG_BINARY+
				  FIELDFLAG_PACK)))
      {
        /* BAR TODO: I'm not sure this should be system_charset_info */
	if (my_sortcmp(system_charset_info,(char*) key,
		       (char*) table->record[0]+key_part->offset,length))
	  return 1;
      }
      else if (memcmp(key,table->record[0]+key_part->offset,length))
	return 1;
    }
  }
  return 0;
}

	/* unpack key-fields from record to some buffer */
	/* This is used to get a good error message */

void key_unpack(String *to,TABLE *table,uint idx)
{
  KEY_PART_INFO *key_part,*key_part_end;
  Field *field;
  String tmp;
  DBUG_ENTER("key_unpack");

  to->length(0);
  for (key_part=table->key_info[idx].key_part,key_part_end=key_part+
	 table->key_info[idx].key_parts ;
       key_part < key_part_end;
       key_part++)
  {
    if (to->length())
      to->append('-');
    if (key_part->null_bit)
    {
      if (table->record[0][key_part->null_offset] & key_part->null_bit)
      {
	to->append("NULL");
	continue;
      }
    }
    if ((field=key_part->field))
    {
      field->val_str(&tmp,&tmp);
      if (key_part->length < field->pack_length())
	tmp.length(min(tmp.length(),key_part->length));
      to->append(tmp);
    }
    else
      to->append("???");
  }
  DBUG_VOID_RETURN;
}


/*
  Return 1 if any field in a list is part of key or the key uses a field
  that is automaticly updated (like a timestamp)
*/

bool check_if_key_used(TABLE *table, uint idx, List<Item> &fields)
{
  List_iterator_fast<Item> f(fields);
  KEY_PART_INFO *key_part,*key_part_end;
  for (key_part=table->key_info[idx].key_part,key_part_end=key_part+
	 table->key_info[idx].key_parts ;
       key_part < key_part_end;
       key_part++)
  {
    Item_field *field;

    if (key_part->field == table->timestamp_field)
      return 1;					// Can't be used for update

    f.rewind();
    while ((field=(Item_field*) f++))
    {
      if (key_part->field == field->field)
	return 1;
    }
  }
  return 0;
}