#structure of tests;
#1 test of table containing single unique blob column;
#2 test of table containing another unique int/ varchar etc column; 
#3 test of table containing multiple unique blob column like unique(a),unique(b);
#4 test of table containing multiple multiple unique blob column like unique(a,b...),unique(c,d....);
#structure of each test;
#test if update works;
#test update for duplicate entry;
#test update for no change keys;
#test update for ignore ;
#test 1
create table t1 (a blob unique);
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	
insert into t1 values(1),(2),(3),(4),(5);
select * from t1;
a
1
2
3
4
5
update t1 set a=11 where a=5;
update t1 set a=a+20 where a=1;
select * from t1;
a
21
2
3
4
11
update t1 set a=3 where a=2;
ERROR 23000: Duplicate entry '3' for key 'a'
update t1 set a=4 where a=3;
ERROR 23000: Duplicate entry '4' for key 'a'
#no change in blob key
update t1 set a=3 where a=3;
update t1 set a=2 where a=2;
select* from t1;
a
21
2
3
4
11
#IGNORE;
update ignore t1 set a=3 where a=2;
update ignore t1 set a=4 where a=3;
select * from t1;
a
21
2
3
4
11
drop table t1;
#test 2;
create table t1 (a int primary key, b blob unique , c int unique );
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
t1	0	PRIMARY	1	a	A	0	NULL	NULL		BTREE		
t1	0	b	1	b	A	NULL	NULL	NULL	YES	HASH		
t1	0	c	1	c	A	NULL	NULL	NULL	YES	BTREE		
insert into t1 values(1,1,1),(2,2,2),(3,3,3),(4,4,4),(5,5,5),(6,6,6),(7,7,7);
select * from t1 limit 3;
a	b	c
1	1	1
2	2	2
3	3	3
update t1 set b=34 where a=1;
update t1 set b=a+c+b+34 where b=2;
update t1 set b=a+10+b where c=3;
select * from t1;
a	b	c
1	34	1
2	40	2
3	16	3
4	4	4
5	5	5
6	6	6
7	7	7
truncate table t1;
insert into t1 values(1,1,1),(2,2,2),(3,3,3),(4,4,4),(5,5,5),(6,6,6),(7,7,7);
update t1 set b=4 where a=3;
ERROR 23000: Duplicate entry '4' for key 'b'
update t1 set b=a+1 where b=3;
ERROR 23000: Duplicate entry '4' for key 'b'
update t1 set b=a+1 where c=3;
ERROR 23000: Duplicate entry '4' for key 'b'
#no change in blob key
update t1 set b=3 where a=3;
update t1 set b=2 where b=2;
update t1 set b=5 where c=5;
select* from t1;
a	b	c
1	1	1
2	2	2
3	3	3
4	4	4
5	5	5
6	6	6
7	7	7
#IGNORE;
update ignore t1 set b=3 where a=2;
update ignore t1 set b=4 where b=3;
update ignore t1 set b=5 where c=3;
select * from t1;
a	b	c
1	1	1
2	2	2
3	3	3
4	4	4
5	5	5
6	6	6
7	7	7
drop table t1;
#test 3;
create table t1 (a blob unique, b blob unique , c blob unique);
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
t1	0	a	1	a	A	NULL	NULL	NULL	YES	HASH		
t1	0	b	1	b	A	NULL	NULL	NULL	YES	HASH		
t1	0	c	1	c	A	NULL	NULL	NULL	YES	HASH		
insert into t1 values(1,1,1),(2,2,2),(3,3,3),(4,4,4),(5,5,5),(6,6,6),(7,7,7);
select * from t1 limit 3;
a	b	c
1	1	1
2	2	2
3	3	3
update t1 set b=34 where a=1;
update t1 set b=a+c+b+34 where b=2;
update t1 set b=a+10+b where c=3;
select * from t1;
a	b	c
1	34	1
2	40	2
3	16	3
4	4	4
5	5	5
6	6	6
7	7	7
truncate table t1;
insert into t1 values(1,1,1),(2,2,2),(3,3,3),(4,4,4),(5,5,5),(6,6,6),(7,7,7);
update t1 set b=4 where a=3;
ERROR 23000: Duplicate entry '4' for key 'b'
update t1 set b=a+1 where b=3;
ERROR 23000: Duplicate entry '4' for key 'b'
update t1 set b=a+1 where c=3;
ERROR 23000: Duplicate entry '4' for key 'b'
#no change in blob key
update t1 set b=3 where a=3;
update t1 set b=2 where b=2;
update t1 set b=5 where c=5;
select* from t1;
a	b	c
1	1	1
2	2	2
3	3	3
4	4	4
5	5	5
6	6	6
7	7	7
#IGNORE;
update ignore t1 set b=3 where a=2;
update ignore t1 set b=4 where b=3;
update ignore t1 set b=5 where c=3;
update ignore t1 set b=b+3 where a>1 or b>1 or c>1;
select * from t1;
a	b	c
1	1	1
2	2	2
3	3	3
4	4	4
5	8	5
6	9	6
7	10	7
update ignore t1 set b=b+5 where a>1 and  b<5 and  c<a+b;
select * from t1;
a	b	c
1	1	1
2	7	2
3	3	3
4	4	4
5	8	5
6	9	6
7	10	7
drop table t1;
#test 4 ultimate test;
create table t1 (a int primary key , b int, c blob , d blob , e  varchar(2000), f int , g text, 
unique (b,c), unique (b,f),unique(e,g),unique(a,b,c,d,e,f,g));
desc t1;
Field	Type	Null	Key	Default	Extra
a	int(11)	NO	PRI	NULL	
b	int(11)	YES	MUL	NULL	
c	blob	YES		NULL	
d	blob	YES		NULL	
e	varchar(2000)	YES	MUL	NULL	
f	int(11)	YES		NULL	
g	text	YES		NULL	
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` int(11) NOT NULL,
  `b` int(11) DEFAULT NULL,
  `c` blob DEFAULT NULL,
  `d` blob DEFAULT NULL,
  `e` varchar(2000) DEFAULT NULL,
  `f` int(11) DEFAULT NULL,
  `g` text DEFAULT NULL,
  PRIMARY KEY (`a`),
  UNIQUE KEY `b` (`b`,`c`) USING HASH,
  UNIQUE KEY `b_2` (`b`,`f`),
  UNIQUE KEY `e` (`e`,`g`) USING HASH,
  UNIQUE KEY `a` (`a`,`b`,`c`,`d`,`e`,`f`,`g`) 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
t1	0	PRIMARY	1	a	A	0	NULL	NULL		BTREE		
t1	0	b	1	b	A	NULL	NULL	NULL	YES	HASH		
t1	0	b	2	c	A	NULL	NULL	NULL	YES	HASH		
t1	0	b_2	1	b	A	NULL	NULL	NULL	YES	BTREE		
t1	0	b_2	2	f	A	NULL	NULL	NULL	YES	BTREE		
t1	0	e	1	e	A	NULL	NULL	NULL	YES	HASH		
t1	0	e	2	g	A	NULL	NULL	NULL	YES	HASH		
t1	0	a	1	a	A	NULL	NULL	NULL		HASH		
t1	0	a	2	b	A	NULL	NULL	NULL	YES	HASH		
t1	0	a	3	c	A	NULL	NULL	NULL	YES	HASH		
t1	0	a	4	d	A	NULL	NULL	NULL	YES	HASH		
t1	0	a	5	e	A	NULL	NULL	NULL	YES	HASH		
t1	0	a	6	f	A	NULL	NULL	NULL	YES	HASH		
t1	0	a	7	g	A	NULL	NULL	NULL	YES	HASH		
insert into t1 values(1,1,1,1,1,1,1),(2,2,2,2,2,2,2),(3,3,3,3,3,3,3),(4,4,4,4,4,4,4),
(5,5,5,5,5,5,5),(6,6,6,6,6,6,6),(7,7,7,7,7,7,7),(8,8,8,8,8,8,8),(9,9,9,9,9,9,9);
select * from t1 limit 3;
a	b	c	d	e	f	g
1	1	1	1	1	1	1
2	2	2	2	2	2	2
3	3	3	3	3	3	3
#key b_c
update t1 set b=2 ,c=2 where a=1;
ERROR 23000: Duplicate entry '2-2' for key 'b'
update t1 set b=b+34, c=c+34 where e=1 and g=1 ;
update t1 set b=35, c=35 where e=1 and g=1 ;
update t1 set b=b+1, c=c+1 where a>0;
ERROR 23000: Duplicate entry '3-3' for key 'b'
update ignore t1 set b=b+1, c=c+1 where a>0;
select * from t1 ;
a	b	c	d	e	f	g
1	37	37	1	1	1	1
2	2	2	2	2	2	2
3	3	3	3	3	3	3
4	4	4	4	4	4	4
5	5	5	5	5	5	5
6	6	6	6	6	6	6
7	7	7	7	7	7	7
8	8	8	8	8	8	8
9	10	10	9	9	9	9
truncate table t1;
insert into t1 values(1,1,1,1,1,1,1),(2,2,2,2,2,2,2),(3,3,3,3,3,3,3),(4,4,4,4,4,4,4),
(5,5,5,5,5,5,5),(6,6,6,6,6,6,6),(7,7,7,7,7,7,7),(8,8,8,8,8,8,8),(9,9,9,9,9,9,9);
#key b_f no hash key
update t1 set b=2 , f=2 where a=1;
ERROR 23000: Duplicate entry '2-2' for key 'b_2'
update  t1 set b=b+33, f=f+33 where e=1 and g=1;
update t1 set b=34, f=34 where e=1 and g=1 ;
update t1 set b=b+1, f=f+1 where a>0;
ERROR 23000: Duplicate entry '3-3' for key 'b_2'
update ignore t1 set b=b+1, f=f+1 where a>0;
select * from t1 ;
a	b	c	d	e	f	g
1	36	1	1	1	36	1
2	2	2	2	2	2	2
3	3	3	3	3	3	3
4	4	4	4	4	4	4
5	5	5	5	5	5	5
6	6	6	6	6	6	6
7	7	7	7	7	7	7
8	8	8	8	8	8	8
9	10	9	9	9	10	9
truncate table t1;
insert into t1 values(1,1,1,1,1,1,1),(2,2,2,2,2,2,2),(3,3,3,3,3,3,3),(4,4,4,4,4,4,4),
(5,5,5,5,5,5,5),(6,6,6,6,6,6,6),(7,7,7,7,7,7,7),(8,8,8,8,8,8,8),(9,9,9,9,9,9,9);
#key e_g
update t1 set e=2 , g=2 where a=1;
ERROR 23000: Duplicate entry '2-2' for key 'e'
update  t1 set e=e+34, g=g+34 where a=1;
update t1 set e=34, g=34 where e=1 and g=1 ;
select * from t1 where  a=1;
a	b	c	d	e	f	g
1	1	1	1	35	1	35
update t1 set e=e+1, g=g+1 where a>0;
ERROR 23000: Duplicate entry '3-3' for key 'e'
update ignore t1 set e=e+1, g=g+1 where a>0;
select * from t1 ;
a	b	c	d	e	f	g
1	1	1	1	37	1	37
2	2	2	2	2	2	2
3	3	3	3	3	3	3
4	4	4	4	4	4	4
5	5	5	5	5	5	5
6	6	6	6	6	6	6
7	7	7	7	7	7	7
8	8	8	8	8	8	8
9	9	9	9	10	9	10
drop table t1;