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
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
|
#Structure of tests
#First we will check all option for
#table containing single unique column
#table containing keys like unique(a,b,c,d) etc
#then table containing 2 blob unique etc
set @allowed_packet= @@max_allowed_packet;
#table with single long blob column;
create table t1(a blob unique );
insert into t1 values(1),(2),(3),(56),('sachin'),('maria'),(123456789034567891),(null),(null),(123456789034567890);
#blob with primary key not allowed
create table t2(a blob,primary key(a(10000)));
ERROR 42000: Specified key was too long; max key length is 1000 bytes
create table t3(a varchar(10000) primary key);
ERROR 42000: Specified key was too long; max key length is 1000 bytes
insert into t1 values(2);
ERROR 23000: Duplicate entry '2' for key 'a'
#table structure;
desc t1;
Field Type Null Key Default Extra
a blob YES UNI NULL
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob DEFAULT NULL,
UNIQUE KEY `a` (`a`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table t1
Non_unique 0
Key_name a
Seq_in_index 1
Column_name a
Collation A
Cardinality NULL
Sub_part NULL
Packed NULL
Null YES
Index_type HASH
Comment
Index_comment
Ignored NO
MyISAM file: DATADIR/test/t1
Record format: Packed
Character set: latin1_swedish_ci (8)
Data records: 10 Deleted blocks: 0
Recordlength: 12
table description:
Key Start Len Index Type
1 12 8 multip. ulonglong NULL
select TABLE_CATALOG,TABLE_SCHEMA,TABLE_NAME,COLUMN_NAME,ORDINAL_POSITION,COLUMN_DEFAULT,IS_NULLABLE,DATA_TYPE,CHARACTER_MAXIMUM_LENGTH,CHARACTER_OCTET_LENGTH,NUMERIC_PRECISION,NUMERIC_SCALE,DATETIME_PRECISION,CHARACTER_SET_NAME,COLLATION_NAME,COLUMN_TYPE,COLUMN_KEY,EXTRA,COLUMN_COMMENT,IS_GENERATED,GENERATION_EXPRESSION from information_schema.columns where table_schema = 'test' and table_name = 't1';
TABLE_CATALOG TABLE_SCHEMA TABLE_NAME COLUMN_NAME ORDINAL_POSITION COLUMN_DEFAULT IS_NULLABLE DATA_TYPE CHARACTER_MAXIMUM_LENGTH CHARACTER_OCTET_LENGTH NUMERIC_PRECISION NUMERIC_SCALE DATETIME_PRECISION CHARACTER_SET_NAME COLLATION_NAME COLUMN_TYPE COLUMN_KEY EXTRA COLUMN_COMMENT IS_GENERATED GENERATION_EXPRESSION
def test t1 a 1 NULL YES blob 65535 65535 NULL NULL NULL NULL NULL blob UNI NEVER NULL
select * from information_schema.statistics where table_schema = 'test' and table_name = 't1';
TABLE_CATALOG TABLE_SCHEMA TABLE_NAME NON_UNIQUE INDEX_SCHEMA INDEX_NAME SEQ_IN_INDEX COLUMN_NAME COLLATION CARDINALITY SUB_PART PACKED NULLABLE INDEX_TYPE COMMENT INDEX_COMMENT IGNORED
def test t1 0 test a 1 a A NULL NULL NULL YES HASH NO
select * from information_schema.key_column_usage where table_schema= 'test' and table_name= 't1';
CONSTRAINT_CATALOG def
CONSTRAINT_SCHEMA test
CONSTRAINT_NAME a
TABLE_CATALOG def
TABLE_SCHEMA test
TABLE_NAME t1
COLUMN_NAME a
ORDINAL_POSITION 1
POSITION_IN_UNIQUE_CONSTRAINT NULL
REFERENCED_TABLE_SCHEMA NULL
REFERENCED_TABLE_NAME NULL
REFERENCED_COLUMN_NAME NULL
# table select we should not be able to see db_row_hash_column;
select * from t1 order by a;
a
NULL
NULL
1
123456789034567890
123456789034567891
2
3
56
maria
sachin
select db_row_hash_1 from t1;
ERROR 42S22: Unknown column 'db_row_hash_1' in 'field list'
#duplicate entry test;
insert into t1 values(2);
ERROR 23000: Duplicate entry '2' for key 'a'
insert into t1 values('sachin');
ERROR 23000: Duplicate entry 'sachin' for key 'a'
insert into t1 values(123456789034567891);
ERROR 23000: Duplicate entry '123456789034567891' for key 'a'
select * from t1 order by a;
a
NULL
NULL
1
123456789034567890
123456789034567891
2
3
56
maria
sachin
insert into t1 values(11),(22),(33);
insert into t1 values(12),(22);
ERROR 23000: Duplicate entry '22' for key 'a'
select * from t1 order by a;
a
NULL
NULL
1
11
12
123456789034567890
123456789034567891
2
22
3
33
56
maria
sachin
insert into t1 values(repeat('s',4000*10)),(repeat('s',4001*10));
insert into t1 values(repeat('m',4000*10)),(repeat('m',4000*10));
ERROR 23000: Duplicate entry 'mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm...' for key 'a'
insert into t1 values(repeat('m',4001)),(repeat('m',4002));
truncate table t1;
insert into t1 values(1),(2),(3),(4),(5),(8),(7);
MyISAM file: DATADIR/test/t1
Record format: Packed
Character set: latin1_swedish_ci (8)
Data records: 7 Deleted blocks: 0
Recordlength: 12
table description:
Key Start Len Index Type
1 12 8 multip. ulonglong NULL
#now some alter commands;
alter table t1 add column b int;
desc t1;
Field Type Null Key Default Extra
a blob YES UNI NULL
b int(11) YES NULL
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob DEFAULT NULL,
`b` int(11) DEFAULT NULL,
UNIQUE KEY `a` (`a`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
insert into t1 values(1,2);
ERROR 23000: Duplicate entry '1' for key 'a'
insert into t1 values(2,2);
ERROR 23000: Duplicate entry '2' for key 'a'
select db_row_hash_1 from t1;
ERROR 42S22: Unknown column 'db_row_hash_1' in 'field list'
#now try to change db_row_hash_1 column;
alter table t1 drop column db_row_hash_1;
ERROR 42000: Can't DROP COLUMN `db_row_hash_1`; check that it exists
alter table t1 add column d int , add column e int , drop column db_row_hash_1;
ERROR 42000: Can't DROP COLUMN `db_row_hash_1`; check that it exists
alter table t1 modify column db_row_hash_1 int ;
ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
alter table t1 add column a int , add column b int, modify column db_row_hash_1 int ;
ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
alter table t1 change column db_row_hash_1 dsds int;
ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
alter table t1 add column asd int, change column db_row_hash_1 dsds int;
ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
alter table t1 drop column b , add column c int;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob DEFAULT NULL,
`c` int(11) DEFAULT NULL,
UNIQUE KEY `a` (`a`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
#now add some column with name db_row_hash;
alter table t1 add column db_row_hash_1 int unique;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob DEFAULT NULL,
`c` int(11) DEFAULT NULL,
`db_row_hash_1` int(11) DEFAULT NULL,
UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
UNIQUE KEY `a` (`a`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
insert into t1 values(45,1,55),(46,1,55);
ERROR 23000: Duplicate entry '55' for key 'db_row_hash_1'
insert into t1 values(45,1,55),(45,1,55);
ERROR 23000: Duplicate entry '45' for key 'a'
alter table t1 add column db_row_hash_2 int, add column db_row_hash_3 int;
desc t1;
Field Type Null Key Default Extra
a blob YES UNI NULL
c int(11) YES NULL
db_row_hash_1 int(11) YES UNI NULL
db_row_hash_2 int(11) YES NULL
db_row_hash_3 int(11) YES NULL
#this should also drop the unique index ;
alter table t1 drop column a;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`c` int(11) DEFAULT NULL,
`db_row_hash_1` int(11) DEFAULT NULL,
`db_row_hash_2` int(11) DEFAULT NULL,
`db_row_hash_3` int(11) DEFAULT NULL,
UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 db_row_hash_1 1 db_row_hash_1 A NULL NULL NULL YES BTREE NO
#add column with unique index on blob ;
alter table t1 add column a blob unique;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`c` int(11) DEFAULT NULL,
`db_row_hash_1` int(11) DEFAULT NULL,
`db_row_hash_2` int(11) DEFAULT NULL,
`db_row_hash_3` int(11) DEFAULT NULL,
`a` blob DEFAULT NULL,
UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
UNIQUE KEY `a` (`a`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
# try to change the blob unique name;
alter table t1 change column a aa blob ;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`c` int(11) DEFAULT NULL,
`db_row_hash_1` int(11) DEFAULT NULL,
`db_row_hash_2` int(11) DEFAULT NULL,
`db_row_hash_3` int(11) DEFAULT NULL,
`aa` blob DEFAULT NULL,
UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
UNIQUE KEY `a` (`aa`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 db_row_hash_1 1 db_row_hash_1 A NULL NULL NULL YES BTREE NO
t1 0 a 1 aa A NULL NULL NULL YES HASH NO
# try to change the blob unique datatype;
#this will change index to b tree;
alter table t1 modify column aa int ;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`c` int(11) DEFAULT NULL,
`db_row_hash_1` int(11) DEFAULT NULL,
`db_row_hash_2` int(11) DEFAULT NULL,
`db_row_hash_3` int(11) DEFAULT NULL,
`aa` int(11) DEFAULT NULL,
UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
UNIQUE KEY `a` (`aa`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 db_row_hash_1 1 db_row_hash_1 A NULL NULL NULL YES BTREE NO
t1 0 a 1 aa A NULL NULL NULL YES BTREE NO
alter table t1 add column clm blob unique;
#try changing the name ;
alter table t1 change column clm clm_changed blob;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`c` int(11) DEFAULT NULL,
`db_row_hash_1` int(11) DEFAULT NULL,
`db_row_hash_2` int(11) DEFAULT NULL,
`db_row_hash_3` int(11) DEFAULT NULL,
`aa` int(11) DEFAULT NULL,
`clm_changed` blob DEFAULT NULL,
UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
UNIQUE KEY `a` (`aa`),
UNIQUE KEY `clm` (`clm_changed`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 db_row_hash_1 1 db_row_hash_1 A NULL NULL NULL YES BTREE NO
t1 0 a 1 aa A NULL NULL NULL YES BTREE NO
t1 0 clm 1 clm_changed A NULL NULL NULL YES HASH NO
#now drop the unique key;
alter table t1 drop key clm;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`c` int(11) DEFAULT NULL,
`db_row_hash_1` int(11) DEFAULT NULL,
`db_row_hash_2` int(11) DEFAULT NULL,
`db_row_hash_3` int(11) DEFAULT NULL,
`aa` int(11) DEFAULT NULL,
`clm_changed` blob DEFAULT NULL,
UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
UNIQUE KEY `a` (`aa`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 db_row_hash_1 1 db_row_hash_1 A NULL NULL NULL YES BTREE NO
t1 0 a 1 aa A NULL NULL NULL YES BTREE NO
drop table t1;
create table t1 (a TEXT CHARSET latin1 COLLATE latin1_german2_ci unique);
desc t1;
Field Type Null Key Default Extra
a text YES UNI NULL
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 a 1 a A NULL NULL NULL YES HASH NO
insert into t1 values ('ae');
insert into t1 values ('AE');
ERROR 23000: Duplicate entry 'AE' for key 'a'
insert into t1 values ('Ä');
drop table t1;
create table t1 (a int primary key, b blob unique);
desc t1;
Field Type Null Key Default Extra
a int(11) NO PRI NULL
b blob YES UNI NULL
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 PRIMARY 1 a A 0 NULL NULL BTREE NO
t1 0 b 1 b A NULL NULL NULL YES HASH NO
insert into t1 values(1,1),(2,2),(3,3);
insert into t1 values(1,1);
ERROR 23000: Duplicate entry '1' for key 'b'
insert into t1 values(7,1);
ERROR 23000: Duplicate entry '1' for key 'b'
drop table t1;
#table with multiple long blob column and varchar text column ;
create table t1(a blob unique, b int , c blob unique , d text unique , e varchar(3000) unique);
insert into t1 values(1,2,3,4,5),(2,11,22,33,44),(3111,222,333,444,555),(5611,2222,3333,4444,5555),
('sachin',341,'fdf','gfgfgfg','hghgr'),('maria',345,'frter','dasd','utyuty'),
(123456789034567891,353534,53453453453456,64565464564564,45435345345345),
(123456789034567890,43545,657567567567,78967657567567,657567567567567676);
#table structure;
desc t1;
Field Type Null Key Default Extra
a blob YES UNI NULL
b int(11) YES NULL
c blob YES UNI NULL
d text YES UNI NULL
e varchar(3000) YES UNI NULL
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob DEFAULT NULL,
`b` int(11) DEFAULT NULL,
`c` blob DEFAULT NULL,
`d` text DEFAULT NULL,
`e` varchar(3000) DEFAULT NULL,
UNIQUE KEY `a` (`a`) USING HASH,
UNIQUE KEY `c` (`c`) USING HASH,
UNIQUE KEY `d` (`d`) USING HASH,
UNIQUE KEY `e` (`e`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 a 1 a A NULL NULL NULL YES HASH NO
t1 0 c 1 c A NULL NULL NULL YES HASH NO
t1 0 d 1 d A NULL NULL NULL YES HASH NO
t1 0 e 1 e A NULL NULL NULL YES HASH NO
MyISAM file: DATADIR/test/t1
Record format: Packed
Character set: latin1_swedish_ci (8)
Data records: 8 Deleted blocks: 0
Recordlength: 3040
table description:
Key Start Len Index Type
1 3039 8 multip. ulonglong NULL
2 3047 8 multip. ulonglong NULL
3 3055 8 multip. ulonglong NULL
4 3063 8 multip. ulonglong NULL
select TABLE_CATALOG,TABLE_SCHEMA,TABLE_NAME,COLUMN_NAME,ORDINAL_POSITION,COLUMN_DEFAULT,IS_NULLABLE,DATA_TYPE,CHARACTER_MAXIMUM_LENGTH,CHARACTER_OCTET_LENGTH,NUMERIC_PRECISION,NUMERIC_SCALE,DATETIME_PRECISION,CHARACTER_SET_NAME,COLLATION_NAME,COLUMN_TYPE,COLUMN_KEY,EXTRA,COLUMN_COMMENT,IS_GENERATED,GENERATION_EXPRESSION from information_schema.columns where table_schema = 'test' and table_name = 't1';
TABLE_CATALOG TABLE_SCHEMA TABLE_NAME COLUMN_NAME ORDINAL_POSITION COLUMN_DEFAULT IS_NULLABLE DATA_TYPE CHARACTER_MAXIMUM_LENGTH CHARACTER_OCTET_LENGTH NUMERIC_PRECISION NUMERIC_SCALE DATETIME_PRECISION CHARACTER_SET_NAME COLLATION_NAME COLUMN_TYPE COLUMN_KEY EXTRA COLUMN_COMMENT IS_GENERATED GENERATION_EXPRESSION
def test t1 a 1 NULL YES blob 65535 65535 NULL NULL NULL NULL NULL blob UNI NEVER NULL
def test t1 b 2 NULL YES int NULL NULL 10 0 NULL NULL NULL int(11) NEVER NULL
def test t1 c 3 NULL YES blob 65535 65535 NULL NULL NULL NULL NULL blob UNI NEVER NULL
def test t1 d 4 NULL YES text 65535 65535 NULL NULL NULL latin1 latin1_swedish_ci text UNI NEVER NULL
def test t1 e 5 NULL YES varchar 3000 3000 NULL NULL NULL latin1 latin1_swedish_ci varchar(3000) UNI NEVER NULL
select * from information_schema.statistics where table_schema = 'test' and table_name = 't1';
TABLE_CATALOG TABLE_SCHEMA TABLE_NAME NON_UNIQUE INDEX_SCHEMA INDEX_NAME SEQ_IN_INDEX COLUMN_NAME COLLATION CARDINALITY SUB_PART PACKED NULLABLE INDEX_TYPE COMMENT INDEX_COMMENT IGNORED
def test t1 0 test a 1 a A NULL NULL NULL YES HASH NO
def test t1 0 test c 1 c A NULL NULL NULL YES HASH NO
def test t1 0 test d 1 d A NULL NULL NULL YES HASH NO
def test t1 0 test e 1 e A NULL NULL NULL YES HASH NO
select * from information_schema.key_column_usage where table_schema= 'test' and table_name= 't1';
CONSTRAINT_CATALOG CONSTRAINT_SCHEMA CONSTRAINT_NAME TABLE_CATALOG TABLE_SCHEMA TABLE_NAME COLUMN_NAME ORDINAL_POSITION POSITION_IN_UNIQUE_CONSTRAINT REFERENCED_TABLE_SCHEMA REFERENCED_TABLE_NAME REFERENCED_COLUMN_NAME
def test a def test t1 a 1 NULL NULL NULL NULL
def test c def test t1 c 1 NULL NULL NULL NULL
def test d def test t1 d 1 NULL NULL NULL NULL
def test e def test t1 e 1 NULL NULL NULL NULL
#table select we should not be able to see db_row_hash_1 column;
select * from t1 order by a;
a b c d e
1 2 3 4 5
123456789034567890 43545 657567567567 78967657567567 657567567567567676
123456789034567891 353534 53453453453456 64565464564564 45435345345345
2 11 22 33 44
3111 222 333 444 555
5611 2222 3333 4444 5555
maria 345 frter dasd utyuty
sachin 341 fdf gfgfgfg hghgr
select db_row_hash_1 from t1;
ERROR 42S22: Unknown column 'db_row_hash_1' in 'field list'
select db_row_hash_2 from t1;
ERROR 42S22: Unknown column 'db_row_hash_2' in 'field list'
select db_row_hash_3 from t1;
ERROR 42S22: Unknown column 'db_row_hash_3' in 'field list'
#duplicate entry test;
insert into t1 values(21,2,3,42,51);
ERROR 23000: Duplicate entry '3' for key 'c'
insert into t1 values('sachin',null,null,null,null);
ERROR 23000: Duplicate entry 'sachin' for key 'a'
insert into t1 values(1234567890345671890,4353451,6575675675617,789676575675617,657567567567567676);
ERROR 23000: Duplicate entry '657567567567567676' for key 'e'
select * from t1 order by a;
a b c d e
1 2 3 4 5
123456789034567890 43545 657567567567 78967657567567 657567567567567676
123456789034567891 353534 53453453453456 64565464564564 45435345345345
2 11 22 33 44
3111 222 333 444 555
5611 2222 3333 4444 5555
maria 345 frter dasd utyuty
sachin 341 fdf gfgfgfg hghgr
insert into t1 values(repeat('s',4000*10),100,repeat('s',4000*10),repeat('s',4000*10),
repeat('s',400)),(repeat('s',4001*10),1000,repeat('s',4001*10),repeat('s',4001*10),
repeat('s',2995));
insert into t1 values(repeat('m',4000*11),10,repeat('s',4000*11),repeat('s',4000*11),repeat('s',2995));
ERROR 23000: Duplicate entry 'sssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss...' for key 'e'
truncate table t1;
insert into t1 values(1,2,3,4,5),(2,11,22,33,44),(3111,222,333,444,555),(5611,2222,3333,4444,5555);
#now some alter commands;
alter table t1 add column f int;
desc t1;
Field Type Null Key Default Extra
a blob YES UNI NULL
b int(11) YES NULL
c blob YES UNI NULL
d text YES UNI NULL
e varchar(3000) YES UNI NULL
f int(11) YES NULL
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob DEFAULT NULL,
`b` int(11) DEFAULT NULL,
`c` blob DEFAULT NULL,
`d` text DEFAULT NULL,
`e` varchar(3000) DEFAULT NULL,
`f` int(11) DEFAULT NULL,
UNIQUE KEY `a` (`a`) USING HASH,
UNIQUE KEY `c` (`c`) USING HASH,
UNIQUE KEY `d` (`d`) USING HASH,
UNIQUE KEY `e` (`e`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
#unique key should not break;
insert into t1 values(1,2,3,4,5,6);
ERROR 23000: Duplicate entry '1' for key 'a'
select db_row_hash_1 , db_row_hash_2, db_row_hash_3 from t1;
ERROR 42S22: Unknown column 'db_row_hash_1' in 'field list'
#now try to change db_row_hash_1 column;
alter table t1 drop column db_row_hash_1, drop column db_row_hash_2, drop column db_row_hash_3;
ERROR 42000: Can't DROP COLUMN `db_row_hash_1`; check that it exists
alter table t1 add column dg int , add column ef int , drop column db_row_hash_1;
ERROR 42000: Can't DROP COLUMN `db_row_hash_1`; check that it exists
alter table t1 modify column db_row_hash_1 int , modify column db_row_hash_2 int, modify column db_row_hash_3 int;
ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
alter table t1 add column ar int , add column rb int, modify column db_row_hash_1 int , modify column db_row_hash_3 int;
ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
alter table t1 change column db_row_hash_1 dsds int , change column db_row_hash_2 dfdf int , change column db_row_hash_3 gdfg int ;
ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
alter table t1 add column asd int, drop column a, change column db_row_hash_1 dsds int, change db_row_hash_3 fdfdfd int;
ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
alter table t1 drop column b , add column g int;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob DEFAULT NULL,
`c` blob DEFAULT NULL,
`d` text DEFAULT NULL,
`e` varchar(3000) DEFAULT NULL,
`f` int(11) DEFAULT NULL,
`g` int(11) DEFAULT NULL,
UNIQUE KEY `a` (`a`) USING HASH,
UNIQUE KEY `c` (`c`) USING HASH,
UNIQUE KEY `d` (`d`) USING HASH,
UNIQUE KEY `e` (`e`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
#now add some column with name db_row_hash;
alter table t1 add column db_row_hash_1 int unique;
alter table t1 add column db_row_hash_2 int unique;
alter table t1 add column db_row_hash_3 int unique;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob DEFAULT NULL,
`c` blob DEFAULT NULL,
`d` text DEFAULT NULL,
`e` varchar(3000) DEFAULT NULL,
`f` int(11) DEFAULT NULL,
`g` int(11) DEFAULT NULL,
`db_row_hash_1` int(11) DEFAULT NULL,
`db_row_hash_2` int(11) DEFAULT NULL,
`db_row_hash_3` int(11) DEFAULT NULL,
UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
UNIQUE KEY `db_row_hash_2` (`db_row_hash_2`),
UNIQUE KEY `db_row_hash_3` (`db_row_hash_3`),
UNIQUE KEY `a` (`a`) USING HASH,
UNIQUE KEY `c` (`c`) USING HASH,
UNIQUE KEY `d` (`d`) USING HASH,
UNIQUE KEY `e` (`e`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
alter table t1 add column db_row_hash_7 int, add column db_row_hash_5 int , add column db_row_hash_4 int ;
alter table t1 drop column db_row_hash_7,drop column db_row_hash_3, drop column db_row_hash_4;
desc t1;
Field Type Null Key Default Extra
a blob YES UNI NULL
c blob YES UNI NULL
d text YES UNI NULL
e varchar(3000) YES UNI NULL
f int(11) YES NULL
g int(11) YES NULL
db_row_hash_1 int(11) YES UNI NULL
db_row_hash_2 int(11) YES UNI NULL
db_row_hash_5 int(11) YES NULL
#this should not break anything;
insert into t1 values(1,2,3,4,5,6,23,5,6);
ERROR 23000: Duplicate entry '1' for key 'a'
#this should also drop the unique index;
alter table t1 drop column a, drop column c;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`d` text DEFAULT NULL,
`e` varchar(3000) DEFAULT NULL,
`f` int(11) DEFAULT NULL,
`g` int(11) DEFAULT NULL,
`db_row_hash_1` int(11) DEFAULT NULL,
`db_row_hash_2` int(11) DEFAULT NULL,
`db_row_hash_5` int(11) DEFAULT NULL,
UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
UNIQUE KEY `db_row_hash_2` (`db_row_hash_2`),
UNIQUE KEY `d` (`d`) USING HASH,
UNIQUE KEY `e` (`e`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 db_row_hash_1 1 db_row_hash_1 A NULL NULL NULL YES BTREE NO
t1 0 db_row_hash_2 1 db_row_hash_2 A NULL NULL NULL YES BTREE NO
t1 0 d 1 d A NULL NULL NULL YES HASH NO
t1 0 e 1 e A NULL NULL NULL YES HASH NO
#add column with unique index on blob;
alter table t1 add column a blob unique;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`d` text DEFAULT NULL,
`e` varchar(3000) DEFAULT NULL,
`f` int(11) DEFAULT NULL,
`g` int(11) DEFAULT NULL,
`db_row_hash_1` int(11) DEFAULT NULL,
`db_row_hash_2` int(11) DEFAULT NULL,
`db_row_hash_5` int(11) DEFAULT NULL,
`a` blob DEFAULT NULL,
UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
UNIQUE KEY `db_row_hash_2` (`db_row_hash_2`),
UNIQUE KEY `d` (`d`) USING HASH,
UNIQUE KEY `e` (`e`) USING HASH,
UNIQUE KEY `a` (`a`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 db_row_hash_1 1 db_row_hash_1 A NULL NULL NULL YES BTREE NO
t1 0 db_row_hash_2 1 db_row_hash_2 A NULL NULL NULL YES BTREE NO
t1 0 d 1 d A NULL NULL NULL YES HASH NO
t1 0 e 1 e A NULL NULL NULL YES HASH NO
t1 0 a 1 a A NULL NULL NULL YES HASH NO
#try to change the blob unique column name;
#this will change index to b tree;
alter table t1 modify column a int , modify column e int;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`d` text DEFAULT NULL,
`e` int(11) DEFAULT NULL,
`f` int(11) DEFAULT NULL,
`g` int(11) DEFAULT NULL,
`db_row_hash_1` int(11) DEFAULT NULL,
`db_row_hash_2` int(11) DEFAULT NULL,
`db_row_hash_5` int(11) DEFAULT NULL,
`a` int(11) DEFAULT NULL,
UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
UNIQUE KEY `db_row_hash_2` (`db_row_hash_2`),
UNIQUE KEY `e` (`e`),
UNIQUE KEY `a` (`a`),
UNIQUE KEY `d` (`d`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 db_row_hash_1 1 db_row_hash_1 A NULL NULL NULL YES BTREE NO
t1 0 db_row_hash_2 1 db_row_hash_2 A NULL NULL NULL YES BTREE NO
t1 0 e 1 e A NULL NULL NULL YES BTREE NO
t1 0 a 1 a A NULL NULL NULL YES BTREE NO
t1 0 d 1 d A NULL NULL NULL YES HASH NO
alter table t1 add column clm1 blob unique,add column clm2 blob unique;
#try changing the name;
alter table t1 change column clm1 clm_changed1 blob, change column clm2 clm_changed2 blob;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`d` text DEFAULT NULL,
`e` int(11) DEFAULT NULL,
`f` int(11) DEFAULT NULL,
`g` int(11) DEFAULT NULL,
`db_row_hash_1` int(11) DEFAULT NULL,
`db_row_hash_2` int(11) DEFAULT NULL,
`db_row_hash_5` int(11) DEFAULT NULL,
`a` int(11) DEFAULT NULL,
`clm_changed1` blob DEFAULT NULL,
`clm_changed2` blob DEFAULT NULL,
UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
UNIQUE KEY `db_row_hash_2` (`db_row_hash_2`),
UNIQUE KEY `e` (`e`),
UNIQUE KEY `a` (`a`),
UNIQUE KEY `d` (`d`) USING HASH,
UNIQUE KEY `clm1` (`clm_changed1`) USING HASH,
UNIQUE KEY `clm2` (`clm_changed2`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 db_row_hash_1 1 db_row_hash_1 A NULL NULL NULL YES BTREE NO
t1 0 db_row_hash_2 1 db_row_hash_2 A NULL NULL NULL YES BTREE NO
t1 0 e 1 e A NULL NULL NULL YES BTREE NO
t1 0 a 1 a A NULL NULL NULL YES BTREE NO
t1 0 d 1 d A NULL NULL NULL YES HASH NO
t1 0 clm1 1 clm_changed1 A NULL NULL NULL YES HASH NO
t1 0 clm2 1 clm_changed2 A NULL NULL NULL YES HASH NO
#now drop the unique key;
alter table t1 drop key clm1, drop key clm2;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`d` text DEFAULT NULL,
`e` int(11) DEFAULT NULL,
`f` int(11) DEFAULT NULL,
`g` int(11) DEFAULT NULL,
`db_row_hash_1` int(11) DEFAULT NULL,
`db_row_hash_2` int(11) DEFAULT NULL,
`db_row_hash_5` int(11) DEFAULT NULL,
`a` int(11) DEFAULT NULL,
`clm_changed1` blob DEFAULT NULL,
`clm_changed2` blob DEFAULT NULL,
UNIQUE KEY `db_row_hash_1` (`db_row_hash_1`),
UNIQUE KEY `db_row_hash_2` (`db_row_hash_2`),
UNIQUE KEY `e` (`e`),
UNIQUE KEY `a` (`a`),
UNIQUE KEY `d` (`d`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 db_row_hash_1 1 db_row_hash_1 A NULL NULL NULL YES BTREE NO
t1 0 db_row_hash_2 1 db_row_hash_2 A NULL NULL NULL YES BTREE NO
t1 0 e 1 e A NULL NULL NULL YES BTREE NO
t1 0 a 1 a A NULL NULL NULL YES BTREE NO
t1 0 d 1 d A NULL NULL NULL YES HASH NO
drop table t1;
#now the table with key on multiple columns; the ultimate test;
create table t1(a blob, b int , c varchar(2000) , d text , e varchar(3000) , f longblob , g int , h text ,
unique(a,b,c), unique(c,d,e),unique(e,f,g,h), unique(b,d,g,h));
insert into t1 values(1,1,1,1,1,1,1,1),(2,2,2,2,2,2,2,2),(3,3,3,3,3,3,3,3),(4,4,4,4,4,4,4,4),(5,5,5,5,5,5,5,5),
('maria',6,'maria','maria','maria','maria',6,'maria'),('mariadb',7,'mariadb','mariadb','mariadb','mariadb',8,'mariadb')
,(null,null,null,null,null,null,null,null),(null,null,null,null,null,null,null,null);
#table structure;
desc t1;
Field Type Null Key Default Extra
a blob YES MUL NULL
b int(11) YES MUL NULL
c varchar(2000) YES MUL NULL
d text YES NULL
e varchar(3000) YES MUL NULL
f longblob YES NULL
g int(11) YES NULL
h text YES NULL
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob DEFAULT NULL,
`b` int(11) DEFAULT NULL,
`c` varchar(2000) DEFAULT NULL,
`d` text DEFAULT NULL,
`e` varchar(3000) DEFAULT NULL,
`f` longblob DEFAULT NULL,
`g` int(11) DEFAULT NULL,
`h` text DEFAULT NULL,
UNIQUE KEY `a` (`a`,`b`,`c`) USING HASH,
UNIQUE KEY `c` (`c`,`d`,`e`) USING HASH,
UNIQUE KEY `e` (`e`,`f`,`g`,`h`) USING HASH,
UNIQUE KEY `b` (`b`,`d`,`g`,`h`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 a 1 a A NULL NULL NULL YES HASH NO
t1 0 a 2 b A NULL NULL NULL YES HASH NO
t1 0 a 3 c A NULL NULL NULL YES HASH NO
t1 0 c 1 c A NULL NULL NULL YES HASH NO
t1 0 c 2 d A NULL NULL NULL YES HASH NO
t1 0 c 3 e A NULL NULL NULL YES HASH NO
t1 0 e 1 e A NULL NULL NULL YES HASH NO
t1 0 e 2 f A NULL NULL NULL YES HASH NO
t1 0 e 3 g A NULL NULL NULL YES HASH NO
t1 0 e 4 h A NULL NULL NULL YES HASH NO
t1 0 b 1 b A NULL NULL NULL YES HASH NO
t1 0 b 2 d A NULL NULL NULL YES HASH NO
t1 0 b 3 g A NULL NULL NULL YES HASH NO
t1 0 b 4 h A NULL NULL NULL YES HASH NO
MyISAM file: DATADIR/test/t1
Record format: Packed
Character set: latin1_swedish_ci (8)
Data records: 9 Deleted blocks: 0
Recordlength: 5059
table description:
Key Start Len Index Type
1 5057 8 multip. ulonglong NULL
2 5065 8 multip. ulonglong NULL
3 5073 8 multip. ulonglong NULL
4 5081 8 multip. ulonglong NULL
select TABLE_CATALOG,TABLE_SCHEMA,TABLE_NAME,COLUMN_NAME,ORDINAL_POSITION,COLUMN_DEFAULT,IS_NULLABLE,DATA_TYPE,CHARACTER_MAXIMUM_LENGTH,CHARACTER_OCTET_LENGTH,NUMERIC_PRECISION,NUMERIC_SCALE,DATETIME_PRECISION,CHARACTER_SET_NAME,COLLATION_NAME,COLUMN_TYPE,COLUMN_KEY,EXTRA,COLUMN_COMMENT,IS_GENERATED,GENERATION_EXPRESSION from information_schema.columns where table_schema = 'test' and table_name = 't1';
TABLE_CATALOG TABLE_SCHEMA TABLE_NAME COLUMN_NAME ORDINAL_POSITION COLUMN_DEFAULT IS_NULLABLE DATA_TYPE CHARACTER_MAXIMUM_LENGTH CHARACTER_OCTET_LENGTH NUMERIC_PRECISION NUMERIC_SCALE DATETIME_PRECISION CHARACTER_SET_NAME COLLATION_NAME COLUMN_TYPE COLUMN_KEY EXTRA COLUMN_COMMENT IS_GENERATED GENERATION_EXPRESSION
def test t1 a 1 NULL YES blob 65535 65535 NULL NULL NULL NULL NULL blob MUL NEVER NULL
def test t1 b 2 NULL YES int NULL NULL 10 0 NULL NULL NULL int(11) MUL NEVER NULL
def test t1 c 3 NULL YES varchar 2000 2000 NULL NULL NULL latin1 latin1_swedish_ci varchar(2000) MUL NEVER NULL
def test t1 d 4 NULL YES text 65535 65535 NULL NULL NULL latin1 latin1_swedish_ci text NEVER NULL
def test t1 e 5 NULL YES varchar 3000 3000 NULL NULL NULL latin1 latin1_swedish_ci varchar(3000) MUL NEVER NULL
def test t1 f 6 NULL YES longblob 4294967295 4294967295 NULL NULL NULL NULL NULL longblob NEVER NULL
def test t1 g 7 NULL YES int NULL NULL 10 0 NULL NULL NULL int(11) NEVER NULL
def test t1 h 8 NULL YES text 65535 65535 NULL NULL NULL latin1 latin1_swedish_ci text NEVER NULL
select * from information_schema.statistics where table_schema = 'test' and table_name = 't1';
TABLE_CATALOG TABLE_SCHEMA TABLE_NAME NON_UNIQUE INDEX_SCHEMA INDEX_NAME SEQ_IN_INDEX COLUMN_NAME COLLATION CARDINALITY SUB_PART PACKED NULLABLE INDEX_TYPE COMMENT INDEX_COMMENT IGNORED
def test t1 0 test a 1 a A NULL NULL NULL YES HASH NO
def test t1 0 test a 2 b A NULL NULL NULL YES HASH NO
def test t1 0 test a 3 c A NULL NULL NULL YES HASH NO
def test t1 0 test c 1 c A NULL NULL NULL YES HASH NO
def test t1 0 test c 2 d A NULL NULL NULL YES HASH NO
def test t1 0 test c 3 e A NULL NULL NULL YES HASH NO
def test t1 0 test e 1 e A NULL NULL NULL YES HASH NO
def test t1 0 test e 2 f A NULL NULL NULL YES HASH NO
def test t1 0 test e 3 g A NULL NULL NULL YES HASH NO
def test t1 0 test e 4 h A NULL NULL NULL YES HASH NO
def test t1 0 test b 1 b A NULL NULL NULL YES HASH NO
def test t1 0 test b 2 d A NULL NULL NULL YES HASH NO
def test t1 0 test b 3 g A NULL NULL NULL YES HASH NO
def test t1 0 test b 4 h A NULL NULL NULL YES HASH NO
select * from information_schema.key_column_usage where table_schema= 'test' and table_name= 't1';
CONSTRAINT_CATALOG CONSTRAINT_SCHEMA CONSTRAINT_NAME TABLE_CATALOG TABLE_SCHEMA TABLE_NAME COLUMN_NAME ORDINAL_POSITION POSITION_IN_UNIQUE_CONSTRAINT REFERENCED_TABLE_SCHEMA REFERENCED_TABLE_NAME REFERENCED_COLUMN_NAME
def test a def test t1 a 1 NULL NULL NULL NULL
def test a def test t1 b 2 NULL NULL NULL NULL
def test a def test t1 c 3 NULL NULL NULL NULL
def test c def test t1 c 1 NULL NULL NULL NULL
def test c def test t1 d 2 NULL NULL NULL NULL
def test c def test t1 e 3 NULL NULL NULL NULL
def test e def test t1 e 1 NULL NULL NULL NULL
def test e def test t1 f 2 NULL NULL NULL NULL
def test e def test t1 g 3 NULL NULL NULL NULL
def test e def test t1 h 4 NULL NULL NULL NULL
def test b def test t1 b 1 NULL NULL NULL NULL
def test b def test t1 d 2 NULL NULL NULL NULL
def test b def test t1 g 3 NULL NULL NULL NULL
def test b def test t1 h 4 NULL NULL NULL NULL
# table select we should not be able to see db_row_hash_1 column;
select * from t1 order by a;
a b c d e f g h
NULL NULL NULL NULL NULL NULL NULL NULL
NULL NULL NULL NULL NULL NULL NULL NULL
1 1 1 1 1 1 1 1
2 2 2 2 2 2 2 2
3 3 3 3 3 3 3 3
4 4 4 4 4 4 4 4
5 5 5 5 5 5 5 5
maria 6 maria maria maria maria 6 maria
mariadb 7 mariadb mariadb mariadb mariadb 8 mariadb
select db_row_hash_1 from t1;
ERROR 42S22: Unknown column 'db_row_hash_1' in 'field list'
select db_row_hash_2 from t1;
ERROR 42S22: Unknown column 'db_row_hash_2' in 'field list'
select db_row_hash_3 from t1;
ERROR 42S22: Unknown column 'db_row_hash_3' in 'field list'
#duplicate entry test;
#duplicate keys entry;
insert into t1 values(1,1,1,0,0,0,0,0);
ERROR 23000: Duplicate entry '1-1-1' for key 'a'
insert into t1 values(0,0,1,1,1,0,0,0);
ERROR 23000: Duplicate entry '1-1-1' for key 'c'
insert into t1 values(0,0,0,0,1,1,1,1);
ERROR 23000: Duplicate entry '1-1-1-1' for key 'e'
insert into t1 values(1,1,1,1,1,0,0,0);
ERROR 23000: Duplicate entry '1-1-1' for key 'a'
insert into t1 values(0,0,0,0,1,1,1,1);
ERROR 23000: Duplicate entry '1-1-1-1' for key 'e'
insert into t1 values(1,1,1,1,1,1,1,1);
ERROR 23000: Duplicate entry '1-1-1' for key 'a'
select db_row_hash_1,db_row_hash_2,db_row_hash_3,db_row_hash_4,db_row_hash_5 from t1;
ERROR 42S22: Unknown column 'db_row_hash_1' in 'field list'
alter table t1 drop column db_row_hash_1, drop column db_row_hash_2, drop column db_row_hash_3;
ERROR 42000: Can't DROP COLUMN `db_row_hash_1`; check that it exists
alter table t1 add column dg int , add column ef int , drop column db_row_hash_1;
ERROR 42000: Can't DROP COLUMN `db_row_hash_1`; check that it exists
alter table t1 modify column db_row_hash_1 int , modify column db_row_hash_2 int, modify column db_row_hash_3 int;
ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
alter table t1 add column ar int , add column rb int, modify column db_row_hash_1 int , modify column db_row_hash_3 int;
ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
alter table t1 change column db_row_hash_1 dsds int , change column db_row_hash_2 dfdf int , change column db_row_hash_3 gdfg int ;
ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
alter table t1 add column asd int, drop column a, change column db_row_hash_1 dsds int, change db_row_hash_3 fdfdfd int;
ERROR 42S22: Unknown column 'db_row_hash_1' in 't1'
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob DEFAULT NULL,
`b` int(11) DEFAULT NULL,
`c` varchar(2000) DEFAULT NULL,
`d` text DEFAULT NULL,
`e` varchar(3000) DEFAULT NULL,
`f` longblob DEFAULT NULL,
`g` int(11) DEFAULT NULL,
`h` text DEFAULT NULL,
UNIQUE KEY `a` (`a`,`b`,`c`) USING HASH,
UNIQUE KEY `c` (`c`,`d`,`e`) USING HASH,
UNIQUE KEY `e` (`e`,`f`,`g`,`h`) USING HASH,
UNIQUE KEY `b` (`b`,`d`,`g`,`h`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
# add column named db_row_hash_*;
alter table t1 add column db_row_hash_7 int , add column db_row_hash_5 int,
add column db_row_hash_1 int, add column db_row_hash_2 int;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob DEFAULT NULL,
`b` int(11) DEFAULT NULL,
`c` varchar(2000) DEFAULT NULL,
`d` text DEFAULT NULL,
`e` varchar(3000) DEFAULT NULL,
`f` longblob DEFAULT NULL,
`g` int(11) DEFAULT NULL,
`h` text DEFAULT NULL,
`db_row_hash_7` int(11) DEFAULT NULL,
`db_row_hash_5` int(11) DEFAULT NULL,
`db_row_hash_1` int(11) DEFAULT NULL,
`db_row_hash_2` int(11) DEFAULT NULL,
UNIQUE KEY `a` (`a`,`b`,`c`) USING HASH,
UNIQUE KEY `c` (`c`,`d`,`e`) USING HASH,
UNIQUE KEY `e` (`e`,`f`,`g`,`h`) USING HASH,
UNIQUE KEY `b` (`b`,`d`,`g`,`h`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 a 1 a A NULL NULL NULL YES HASH NO
t1 0 a 2 b A NULL NULL NULL YES HASH NO
t1 0 a 3 c A NULL NULL NULL YES HASH NO
t1 0 c 1 c A NULL NULL NULL YES HASH NO
t1 0 c 2 d A NULL NULL NULL YES HASH NO
t1 0 c 3 e A NULL NULL NULL YES HASH NO
t1 0 e 1 e A NULL NULL NULL YES HASH NO
t1 0 e 2 f A NULL NULL NULL YES HASH NO
t1 0 e 3 g A NULL NULL NULL YES HASH NO
t1 0 e 4 h A NULL NULL NULL YES HASH NO
t1 0 b 1 b A NULL NULL NULL YES HASH NO
t1 0 b 2 d A NULL NULL NULL YES HASH NO
t1 0 b 3 g A NULL NULL NULL YES HASH NO
t1 0 b 4 h A NULL NULL NULL YES HASH NO
alter table t1 drop column db_row_hash_7 , drop column db_row_hash_5 ,
drop column db_row_hash_1, drop column db_row_hash_2 ;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob DEFAULT NULL,
`b` int(11) DEFAULT NULL,
`c` varchar(2000) DEFAULT NULL,
`d` text DEFAULT NULL,
`e` varchar(3000) DEFAULT NULL,
`f` longblob DEFAULT NULL,
`g` int(11) DEFAULT NULL,
`h` text DEFAULT NULL,
UNIQUE KEY `a` (`a`,`b`,`c`) USING HASH,
UNIQUE KEY `c` (`c`,`d`,`e`) USING HASH,
UNIQUE KEY `e` (`e`,`f`,`g`,`h`) USING HASH,
UNIQUE KEY `b` (`b`,`d`,`g`,`h`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 a 1 a A NULL NULL NULL YES HASH NO
t1 0 a 2 b A NULL NULL NULL YES HASH NO
t1 0 a 3 c A NULL NULL NULL YES HASH NO
t1 0 c 1 c A NULL NULL NULL YES HASH NO
t1 0 c 2 d A NULL NULL NULL YES HASH NO
t1 0 c 3 e A NULL NULL NULL YES HASH NO
t1 0 e 1 e A NULL NULL NULL YES HASH NO
t1 0 e 2 f A NULL NULL NULL YES HASH NO
t1 0 e 3 g A NULL NULL NULL YES HASH NO
t1 0 e 4 h A NULL NULL NULL YES HASH NO
t1 0 b 1 b A NULL NULL NULL YES HASH NO
t1 0 b 2 d A NULL NULL NULL YES HASH NO
t1 0 b 3 g A NULL NULL NULL YES HASH NO
t1 0 b 4 h A NULL NULL NULL YES HASH NO
#try to change column names;
alter table t1 change column a aa blob , change column b bb blob , change column d dd blob;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`aa` blob DEFAULT NULL,
`bb` blob DEFAULT NULL,
`c` varchar(2000) DEFAULT NULL,
`dd` blob DEFAULT NULL,
`e` varchar(3000) DEFAULT NULL,
`f` longblob DEFAULT NULL,
`g` int(11) DEFAULT NULL,
`h` text DEFAULT NULL,
UNIQUE KEY `a` (`aa`,`bb`,`c`) USING HASH,
UNIQUE KEY `c` (`c`,`dd`,`e`) USING HASH,
UNIQUE KEY `e` (`e`,`f`,`g`,`h`) USING HASH,
UNIQUE KEY `b` (`bb`,`dd`,`g`,`h`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 a 1 aa A NULL NULL NULL YES HASH NO
t1 0 a 2 bb A NULL NULL NULL YES HASH NO
t1 0 a 3 c A NULL NULL NULL YES HASH NO
t1 0 c 1 c A NULL NULL NULL YES HASH NO
t1 0 c 2 dd A NULL NULL NULL YES HASH NO
t1 0 c 3 e A NULL NULL NULL YES HASH NO
t1 0 e 1 e A NULL NULL NULL YES HASH NO
t1 0 e 2 f A NULL NULL NULL YES HASH NO
t1 0 e 3 g A NULL NULL NULL YES HASH NO
t1 0 e 4 h A NULL NULL NULL YES HASH NO
t1 0 b 1 bb A NULL NULL NULL YES HASH NO
t1 0 b 2 dd A NULL NULL NULL YES HASH NO
t1 0 b 3 g A NULL NULL NULL YES HASH NO
t1 0 b 4 h A NULL NULL NULL YES HASH NO
alter table t1 change column aa a blob , change column bb b blob , change column dd d blob;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob DEFAULT NULL,
`b` blob DEFAULT NULL,
`c` varchar(2000) DEFAULT NULL,
`d` blob DEFAULT NULL,
`e` varchar(3000) DEFAULT NULL,
`f` longblob DEFAULT NULL,
`g` int(11) DEFAULT NULL,
`h` text DEFAULT NULL,
UNIQUE KEY `a` (`a`,`b`,`c`) USING HASH,
UNIQUE KEY `c` (`c`,`d`,`e`) USING HASH,
UNIQUE KEY `e` (`e`,`f`,`g`,`h`) USING HASH,
UNIQUE KEY `b` (`b`,`d`,`g`,`h`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 a 1 a A NULL NULL NULL YES HASH NO
t1 0 a 2 b A NULL NULL NULL YES HASH NO
t1 0 a 3 c A NULL NULL NULL YES HASH NO
t1 0 c 1 c A NULL NULL NULL YES HASH NO
t1 0 c 2 d A NULL NULL NULL YES HASH NO
t1 0 c 3 e A NULL NULL NULL YES HASH NO
t1 0 e 1 e A NULL NULL NULL YES HASH NO
t1 0 e 2 f A NULL NULL NULL YES HASH NO
t1 0 e 3 g A NULL NULL NULL YES HASH NO
t1 0 e 4 h A NULL NULL NULL YES HASH NO
t1 0 b 1 b A NULL NULL NULL YES HASH NO
t1 0 b 2 d A NULL NULL NULL YES HASH NO
t1 0 b 3 g A NULL NULL NULL YES HASH NO
t1 0 b 4 h A NULL NULL NULL YES HASH NO
#now we will change the data type to int and varchar limit so that we no longer require hash_index;
#on key a_b_c;
alter table t1 modify column a varchar(20) , modify column b varchar(20) , modify column c varchar(20);
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` varchar(20) DEFAULT NULL,
`b` varchar(20) DEFAULT NULL,
`c` varchar(20) DEFAULT NULL,
`d` blob DEFAULT NULL,
`e` varchar(3000) DEFAULT NULL,
`f` longblob DEFAULT NULL,
`g` int(11) DEFAULT NULL,
`h` text DEFAULT NULL,
UNIQUE KEY `a` (`a`,`b`,`c`),
UNIQUE KEY `c` (`c`,`d`,`e`) USING HASH,
UNIQUE KEY `e` (`e`,`f`,`g`,`h`) USING HASH,
UNIQUE KEY `b` (`b`,`d`,`g`,`h`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 a 1 a A NULL NULL NULL YES BTREE NO
t1 0 a 2 b A NULL NULL NULL YES BTREE NO
t1 0 a 3 c A NULL NULL NULL YES BTREE NO
t1 0 c 1 c A NULL NULL NULL YES HASH NO
t1 0 c 2 d A NULL NULL NULL YES HASH NO
t1 0 c 3 e A NULL NULL NULL YES HASH NO
t1 0 e 1 e A NULL NULL NULL YES HASH NO
t1 0 e 2 f A NULL NULL NULL YES HASH NO
t1 0 e 3 g A NULL NULL NULL YES HASH NO
t1 0 e 4 h A NULL NULL NULL YES HASH NO
t1 0 b 1 b A NULL NULL NULL YES HASH NO
t1 0 b 2 d A NULL NULL NULL YES HASH NO
t1 0 b 3 g A NULL NULL NULL YES HASH NO
t1 0 b 4 h A NULL NULL NULL YES HASH NO
#change it back;
alter table t1 modify column a blob , modify column b blob , modify column c blob;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob DEFAULT NULL,
`b` blob DEFAULT NULL,
`c` blob DEFAULT NULL,
`d` blob DEFAULT NULL,
`e` varchar(3000) DEFAULT NULL,
`f` longblob DEFAULT NULL,
`g` int(11) DEFAULT NULL,
`h` text DEFAULT NULL,
UNIQUE KEY `a` (`a`,`b`,`c`) USING HASH,
UNIQUE KEY `c` (`c`,`d`,`e`) USING HASH,
UNIQUE KEY `e` (`e`,`f`,`g`,`h`) USING HASH,
UNIQUE KEY `b` (`b`,`d`,`g`,`h`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 a 1 a A NULL NULL NULL YES HASH NO
t1 0 a 2 b A NULL NULL NULL YES HASH NO
t1 0 a 3 c A NULL NULL NULL YES HASH NO
t1 0 c 1 c A NULL NULL NULL YES HASH NO
t1 0 c 2 d A NULL NULL NULL YES HASH NO
t1 0 c 3 e A NULL NULL NULL YES HASH NO
t1 0 e 1 e A NULL NULL NULL YES HASH NO
t1 0 e 2 f A NULL NULL NULL YES HASH NO
t1 0 e 3 g A NULL NULL NULL YES HASH NO
t1 0 e 4 h A NULL NULL NULL YES HASH NO
t1 0 b 1 b A NULL NULL NULL YES HASH NO
t1 0 b 2 d A NULL NULL NULL YES HASH NO
t1 0 b 3 g A NULL NULL NULL YES HASH NO
t1 0 b 4 h A NULL NULL NULL YES HASH NO
#try to delete blob column in unique;
truncate table t1;
#now try to delete keys;
alter table t1 drop key c, drop key e;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob DEFAULT NULL,
`b` blob DEFAULT NULL,
`c` blob DEFAULT NULL,
`d` blob DEFAULT NULL,
`e` varchar(3000) DEFAULT NULL,
`f` longblob DEFAULT NULL,
`g` int(11) DEFAULT NULL,
`h` text DEFAULT NULL,
UNIQUE KEY `a` (`a`,`b`,`c`) USING HASH,
UNIQUE KEY `b` (`b`,`d`,`g`,`h`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 a 1 a A NULL NULL NULL YES HASH NO
t1 0 a 2 b A NULL NULL NULL YES HASH NO
t1 0 a 3 c A NULL NULL NULL YES HASH NO
t1 0 b 1 b A NULL NULL NULL YES HASH NO
t1 0 b 2 d A NULL NULL NULL YES HASH NO
t1 0 b 3 g A NULL NULL NULL YES HASH NO
t1 0 b 4 h A NULL NULL NULL YES HASH NO
drop table t1;
#now alter table containing some data basically some tests with ignore;
create table t1 (a blob);
insert into t1 values(1),(2),(3);
#normal alter table;
alter table t1 add unique key(a);
alter table t1 drop key a;
truncate table t1;
insert into t1 values(1),(1),(2),(2),(3);
alter table t1 add unique key(a);
ERROR 23000: Duplicate entry '1' for key 'a'
alter ignore table t1 add unique key(a);
select * from t1 order by a;
a
1
2
3
insert into t1 values(1);
ERROR 23000: Duplicate entry '1' for key 'a'
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob DEFAULT NULL,
UNIQUE KEY `a` (`a`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 a 1 a A NULL NULL NULL YES HASH NO
drop table t1;
#Now with multiple keys;
create table t1(a blob , b blob, c blob , d blob , e int);
insert into t1 values (1,1,1,1,1);
insert into t1 values (1,1,1,1,1);
insert into t1 values (2,1,1,1,1);
insert into t1 values (2,2,2,2,2);
insert into t1 values (3,3,4,4,4);
insert into t1 values (4,4,4,4,4);
alter table t1 add unique key(a,c), add unique key(b,d), add unique key(e);
ERROR 23000: Duplicate entry '1-1' for key 'a'
alter ignore table t1 add unique key(a,c), add unique key(b,d), add unique key(e);
select * from t1 order by a;
a b c d e
1 1 1 1 1
2 2 2 2 2
3 3 4 4 4
insert into t1 values (1,12,1,13,14);
ERROR 23000: Duplicate entry '1-1' for key 'a'
insert into t1 values (12,1,14,1,14);
ERROR 23000: Duplicate entry '1-1' for key 'b'
insert into t1 values (13,12,13,14,4);
ERROR 23000: Duplicate entry '4' for key 'e'
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob DEFAULT NULL,
`b` blob DEFAULT NULL,
`c` blob DEFAULT NULL,
`d` blob DEFAULT NULL,
`e` int(11) DEFAULT NULL,
UNIQUE KEY `e` (`e`),
UNIQUE KEY `a` (`a`,`c`) USING HASH,
UNIQUE KEY `b` (`b`,`d`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 e 1 e A NULL NULL NULL YES BTREE NO
t1 0 a 1 a A NULL NULL NULL YES HASH NO
t1 0 a 2 c A NULL NULL NULL YES HASH NO
t1 0 b 1 b A NULL NULL NULL YES HASH NO
t1 0 b 2 d A NULL NULL NULL YES HASH NO
drop table t1;
#visibility of db_row_hash
create table t1 (a blob unique , b blob unique);
desc t1;
Field Type Null Key Default Extra
a blob YES UNI NULL
b blob YES UNI NULL
insert into t1 values(1,19);
insert into t1 values(2,29);
insert into t1 values(3,39);
insert into t1 values(4,49);
create table t2 (DB_ROW_HASH_1 int, DB_ROW_HASH_2 int);
insert into t2 values(11,1);
insert into t2 values(22,2);
insert into t2 values(33,3);
insert into t2 values(44,4);
select * from t1 order by a;
a b
1 19
2 29
3 39
4 49
select * from t2 order by DB_ROW_HASH_1;
DB_ROW_HASH_1 DB_ROW_HASH_2
11 1
22 2
33 3
44 4
select DB_ROW_HASH_1, DB_ROW_HASH_2 from t1;
ERROR 42S22: Unknown column 'DB_ROW_HASH_1' in 'field list'
#bug
select DB_ROW_HASH_1, DB_ROW_HASH_2 from t1,t2;
DB_ROW_HASH_1 DB_ROW_HASH_2
11 1
11 1
11 1
11 1
22 2
22 2
22 2
22 2
33 3
33 3
33 3
33 3
44 4
44 4
44 4
44 4
select * from t1 where DB_ROW_HASH_1 in (select DB_ROW_HASH_1 from t2);
ERROR 42S22: Unknown column 'DB_ROW_HASH_1' in 'IN/ALL/ANY subquery'
select DB_ROW_HASH_1, DB_ROW_HASH_2 from t1,t2 where DB_ROW_HASH_1 in (select DB_ROW_HASH_1 from t2);
DB_ROW_HASH_1 DB_ROW_HASH_2
11 1
22 2
33 3
44 4
11 1
22 2
33 3
44 4
11 1
22 2
33 3
44 4
11 1
22 2
33 3
44 4
select * from t2 where DB_ROW_HASH_1 in (select DB_ROW_HASH_1 from t1);
DB_ROW_HASH_1 DB_ROW_HASH_2
11 1
22 2
33 3
44 4
select DB_ROW_HASH_1 from t1,t2 where t1.DB_ROW_HASH_1 = t2.DB_ROW_HASH_2;
ERROR 42S22: Unknown column 't1.DB_ROW_HASH_1' in 'where clause'
select DB_ROW_HASH_1 from t1 inner join t2 on t1.a = t2.DB_ROW_HASH_2;
DB_ROW_HASH_1
11
22
33
44
drop table t1,t2;
#very long blob entry;
SET @@GLOBAL.max_allowed_packet=67108864;
connect 'newcon', localhost, root,,;
connection newcon;
show variables like 'max_allowed_packet';
Variable_name Value
max_allowed_packet 67108864
create table t1(a longblob unique, b longblob , c longblob , unique(b,c));
desc t1;
Field Type Null Key Default Extra
a longblob YES UNI NULL
b longblob YES MUL NULL
c longblob YES NULL
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` longblob DEFAULT NULL,
`b` longblob DEFAULT NULL,
`c` longblob DEFAULT NULL,
UNIQUE KEY `a` (`a`) USING HASH,
UNIQUE KEY `b` (`b`,`c`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 a 1 a A NULL NULL NULL YES HASH NO
t1 0 b 1 b A NULL NULL NULL YES HASH NO
t1 0 b 2 c A NULL NULL NULL YES HASH NO
insert into t1 values(concat(repeat('sachin',10000000),'1'),concat(repeat('sachin',10000000),'1'),
concat(repeat('sachin',10000000),'1'));
insert into t1 values(concat(repeat('sachin',10000000),'2'),concat(repeat('sachin',10000000),'2'),
concat(repeat('sachin',10000000),'1'));
insert into t1 values(concat(repeat('sachin',10000000),'2'),concat(repeat('sachin',10000000),'2'),
concat(repeat('sachin',10000000),'4'));
ERROR 23000: Duplicate entry 'sachinsachinsachinsachinsachinsachinsachinsachinsachinsachins...' for key 'a'
insert into t1 values(concat(repeat('sachin',10000000),'3'),concat(repeat('sachin',10000000),'1'),
concat(repeat('sachin',10000000),'1'));
ERROR 23000: Duplicate entry 'sachinsachinsachinsachinsachinsachinsachinsachinsachinsachins...' for key 'b'
drop table t1;
#long key unique with different key length
create table t1(a blob, unique(a(3000)));
desc t1;
Field Type Null Key Default Extra
a blob YES UNI NULL
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 a 1 a A NULL 3000 NULL YES HASH NO
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob DEFAULT NULL,
UNIQUE KEY `a` (`a`(3000)) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
insert into t1 value(concat(repeat('s',3000),'1'));
insert into t1 value(concat(repeat('s',3000),'2'));
ERROR 23000: Duplicate entry 'sssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss...' for key 'a'
insert into t1 value(concat(repeat('a',3000),'2'));
drop table t1;
create table t1(a varchar(4000), b longblob , c varchar(5000), d longblob,
unique(a(3500), b), unique(c(4500), d));
desc t1;
Field Type Null Key Default Extra
a varchar(4000) YES MUL NULL
b longblob YES NULL
c varchar(5000) YES MUL NULL
d longblob YES NULL
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` varchar(4000) DEFAULT NULL,
`b` longblob DEFAULT NULL,
`c` varchar(5000) DEFAULT NULL,
`d` longblob DEFAULT NULL,
UNIQUE KEY `a` (`a`(3500),`b`) USING HASH,
UNIQUE KEY `c` (`c`(4500),`d`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
show keys from t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 a 1 a A NULL 3500 NULL YES HASH NO
t1 0 a 2 b A NULL NULL NULL YES HASH NO
t1 0 c 1 c A NULL 4500 NULL YES HASH NO
t1 0 c 2 d A NULL NULL NULL YES HASH NO
drop table t1;
disconnect newcon;
connection default;
SET @@GLOBAL.max_allowed_packet=4194304;
#ext bug
create table t1(a int primary key, b blob unique, c int, d blob , index(c));
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` int(11) NOT NULL,
`b` blob DEFAULT NULL,
`c` int(11) DEFAULT NULL,
`d` blob DEFAULT NULL,
PRIMARY KEY (`a`),
UNIQUE KEY `b` (`b`) USING HASH,
KEY `c` (`c`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
insert into t1 values(1,23,1,33);
insert into t1 values(2,23,1,33);
ERROR 23000: Duplicate entry '23' for key 'b'
drop table t1;
create table t2 (a blob unique , c int , index(c));
show create table t2;
Table Create Table
t2 CREATE TABLE `t2` (
`a` blob DEFAULT NULL,
`c` int(11) DEFAULT NULL,
UNIQUE KEY `a` (`a`) USING HASH,
KEY `c` (`c`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
insert into t2 values(1,1);
insert into t2 values(2,1);
drop table t2;
#not null test
create table t1(a blob unique not null);
desc t1;
Field Type Null Key Default Extra
a blob NO UNI NULL
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob NOT NULL,
UNIQUE KEY `a` (`a`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
insert into t1 values(1);
insert into t1 values(3);
insert into t1 values(1);
ERROR 23000: Duplicate entry '1' for key 'a'
drop table t1;
create table t1(a int primary key, b blob unique , c blob unique not null);
insert into t1 values(1,1,1);
insert into t1 values(2,1,2);
ERROR 23000: Duplicate entry '1' for key 'b'
insert into t1 values(3,3,1);
ERROR 23000: Duplicate entry '1' for key 'c'
drop table t1;
create table t1 (a blob unique not null, b blob not null, c blob not null, unique(b,c));
desc t1;
Field Type Null Key Default Extra
a blob NO UNI NULL
b blob NO MUL NULL
c blob NO NULL
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob NOT NULL,
`b` blob NOT NULL,
`c` blob NOT NULL,
UNIQUE KEY `a` (`a`) USING HASH,
UNIQUE KEY `b` (`b`,`c`) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
insert into t1 values (1, 2, 3);
insert into t1 values (2, 1, 3);
insert into t1 values (2, 1, 3);
ERROR 23000: Duplicate entry '2' for key 'a'
drop table t1;
#partition
create table t1(a blob unique) partition by hash(a);
ERROR HY000: A BLOB field is not allowed in partition function
#key length > 2^16 -1
create table t1(a blob, unique(a(65536)));
ERROR 42000: Specified key part was too long; max key part length is 65535 bytes
create table t1(a blob, unique(a(65535)));
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob DEFAULT NULL,
UNIQUE KEY `a` (`a`(65535)) USING HASH
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
#64 indexes
create table t1 ( a63 blob unique, a62 blob unique, a61 blob unique, a60 blob unique, a59 blob unique, a58 blob unique, a57 blob unique, a56 blob unique, a55 blob unique, a54 blob unique, a53 blob unique, a52 blob unique, a51 blob unique, a50 blob unique, a49 blob unique, a48 blob unique, a47 blob unique, a46 blob unique, a45 blob unique, a44 blob unique, a43 blob unique, a42 blob unique, a41 blob unique, a40 blob unique, a39 blob unique, a38 blob unique, a37 blob unique, a36 blob unique, a35 blob unique, a34 blob unique, a33 blob unique, a32 blob unique, a31 blob unique, a30 blob unique, a29 blob unique, a28 blob unique, a27 blob unique, a26 blob unique, a25 blob unique, a24 blob unique, a23 blob unique, a22 blob unique, a21 blob unique, a20 blob unique, a19 blob unique, a18 blob unique, a17 blob unique, a16 blob unique, a15 blob unique, a14 blob unique, a13 blob unique, a12 blob unique, a11 blob unique, a10 blob unique, a9 blob unique, a8 blob unique, a7 blob unique, a6 blob unique, a5 blob unique, a4 blob unique, a3 blob unique, a2 blob unique, a1 blob unique, a blob unique);;
insert into t1 values( 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0);;
insert into t1 values( 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0);;
ERROR 23000: Duplicate entry '63' for key 'a63'
insert into t1 values( 0, 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);;
insert into t1 values( 0, 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);;
ERROR 23000: Duplicate entry '0' for key 'a63'
drop table t1;
create table t1(a blob , key(a));
Warnings:
Note 1071 Specified key was too long; max key length is 1000 bytes
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob DEFAULT NULL,
KEY `a` (`a`(1000))
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1(a blob);
alter table t1 add index(a);
Warnings:
Note 1071 Specified key was too long; max key length is 1000 bytes
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` blob DEFAULT NULL,
KEY `a` (`a`(1000))
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1(a text, key(a));
Warnings:
Note 1071 Specified key was too long; max key length is 1000 bytes
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` text DEFAULT NULL,
KEY `a` (`a`(1000))
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1(a varchar(4000));
alter table t1 add index(a);
Warnings:
Note 1071 Specified key was too long; max key length is 1000 bytes
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` varchar(4000) DEFAULT NULL,
KEY `a` (`a`(1000))
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
create table t1 (pk int, a int, b int, primary key(pk), key(pk,a));
alter table t1 modify a text;
ERROR 42000: Specified key was too long; max key length is 1000 bytes
alter table t1 modify a varchar(1000);
ERROR 42000: Specified key was too long; max key length is 1000 bytes
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`pk` int(11) NOT NULL,
`a` int(11) DEFAULT NULL,
`b` int(11) DEFAULT NULL,
PRIMARY KEY (`pk`),
KEY `pk` (`pk`,`a`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
#
# MDEV-19705: Assertion `tmp >= 0' failed in best_access_path
#
CREATE TABLE t1 (d varchar(10)) ENGINE=MyISAM;
INSERT INTO t1 VALUES ('a'),('q');
CREATE TABLE t2 (f varchar(10), a2 datetime, b int, a1 varchar(1024), pk int NOT NULL, PRIMARY KEY (pk), UNIQUE KEY (f,a1,a2), KEY f2 (f(4),a2)) ENGINE=MyISAM;
INSERT INTO t2 VALUES ('aaa','1985-09-06',-163,'s',1),('bbb','1995-01-05',3,'pucaz',2),('ccc','0000-00-00',NULL,'help',3),('ddd',NULL,618,'v',4),('eee','1995-12-20',410,'m',5),('ffq','1976-06-12 20:02:56',NULL,'POKNC',6),('dddd','0000-00-00',-328,'hgsu',7);
explain
SELECT t2.b FROM t1 JOIN t2 ON t1.d = t2.f WHERE t2.pk >= 20;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range PRIMARY,f,f2 PRIMARY 4 NULL 1 Using index condition
1 SIMPLE t1 ALL NULL NULL NULL NULL 2 Using where; Using join buffer (flat, BNL join)
SELECT t2.b FROM t1 JOIN t2 ON t1.d = t2.f WHERE t2.pk >= 20;
b
drop table t1,t2;
#
# MDEV-21470 MyISAM start_bulk_insert doesn't work with long unique
#
CREATE TABLE t1 (a INT, b BLOB) ENGINE=MyISAM;
INSERT INTO t1 VALUES (1,'foo'),(2,'bar');
CREATE TABLE t2 (c BIT, d BLOB, UNIQUE(d)) ENGINE=MyISAM;
INSERT INTO t2 SELECT * FROM t1;
Warnings:
Warning 1264 Out of range value for column 'c' at row 2
DROP TABLE t1, t2;
#
# MDEV-19338 Using AUTO_INCREMENT with long unique
#
CREATE TABLE t1 (pk INT, a TEXT NOT NULL DEFAULT '', PRIMARY KEY (pk), b INT AUTO_INCREMENT, UNIQUE(b), UNIQUE (a,b)) ENGINE=myisam;
ERROR HY000: AUTO_INCREMENT column `b` cannot be used in the UNIQUE index `a`
set @@GLOBAL.max_allowed_packet= @allowed_packet;
|