CREATE TABLE t1 (
id int(11) NOT NULL PRIMARY KEY,
a int(11) NOT NULL,
b int(11) NOT NULL,
c int not null,
CONSTRAINT test FOREIGN KEY (b) REFERENCES t1 (id)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
CREATE TABLE t2 (
id int(11) NOT NULL PRIMARY KEY,
a int(11) NOT NULL,
b int(11) NOT NULL,
c int not null,
CONSTRAINT mytest FOREIGN KEY (c) REFERENCES t1(id),
CONSTRAINT test FOREIGN KEY (b) REFERENCES t2 (id)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
show warnings;
Level Code Message
drop table t2,t1;
create table t1(a int) engine=innodb;
create table t2(a int, constraint a foreign key a (a) references t1(a)) engine=innodb; ERROR HY000: Can't create table `test`.`t2` (errno: 150 "Foreign key constraint is incorrectly formed")
show warnings;
Level Code Message
Warning 150 Create table `test`.`t2` with foreign key `a` constraint failed. There is no index in the referenced table where the referenced columns appear as the first columns. Error1005 Can't create table `test`.`t2` (errno: 150 "Foreign key constraint is incorrectly formed")
Warning 1215 Cannot add foreign key constraint for `t2`
drop table t1;
create table t1(a int unique, b int) engine=innodb;
create table t2(a int, b int, foreign key (a) references t1(a), foreign key (b) references t1(b)) engine=innodb; ERROR HY000: Can't create table `test`.`t2` (errno: 150 "Foreign key constraint is incorrectly formed")
show warnings;
Level Code Message
Warning 150 Create table `test`.`t2` with foreign key (b) constraint failed. There is no index in the referenced table where the referenced columns appear as the first columns. Error1005 Can't create table `test`.`t2` (errno: 150 "Foreign key constraint is incorrectly formed")
Warning 1215 Cannot add foreign key constraint for `t2`
drop table t1;
create table t1(a int not null primary key, b int) engine=innodb;
create table t2(a int, b int, constraint a foreign key a (a) references t1(a),
constraint a foreign key a (a) references t1(b)) engine=innodb; ERROR HY000: Can't create table `test`.`t2` (errno: 150 "Foreign key constraint is incorrectly formed")
show warnings;
Level Code Message Error1005 Can't create table `test`.`t2` (errno: 150 "Foreign key constraint is incorrectly formed")
Warning 1215 Cannot add foreign key constraint for `t2`
create table t2(a int, b int, constraint a foreign key a (a) references t1(a)) engine=innodb;
alter table t2 add constraint b foreign key (b) references t2(b); ERROR HY000: Can't create temporary table for ALTER TABLE `test`.`t2` (errno: 150 "Foreign key constraint is incorrectly formed")
show warnings;
Level Code Message
Warning 150 Alter table `test`.`t2` with foreign key `b` constraint failed. There is no index in the referenced table where the referenced columns appear as the first columns. Error1005 Can't create temporary table for ALTER TABLE `test`.`t2` (errno: 150 "Foreign key constraint is incorrectly formed")
Warning 1215 Cannot add foreign key constraint for `t2`
drop table t2, t1;
create table t1 (f1 integer primary key) engine=innodb;
alter table t1 add constraint c1 foreign key (f1) references t11(f1); ERROR HY000: Can't create temporary table for ALTER TABLE `test`.`t1` (errno: 150 "Foreign key constraint is incorrectly formed")
show warnings;
Level Code Message
Warning 150 Alter table `test`.`t1` with foreign key `c1` constraint failed. Referenced table `test`.`t11` not found in the data dictionary. Error1005 Can't create temporary table for ALTER TABLE `test`.`t1` (errno: 150 "Foreign key constraint is incorrectly formed")
Warning 1215 Cannot add foreign key constraint for `t1`
drop table t1;
create temporary table t1(a int not null primary key, b int, key(b)) engine=innodb;
create temporary table t2(a int, foreign key(a) references t1(a)) engine=innodb; ERROR HY000: Can't create table `test`.`t2` (errno: 150 "Foreign key constraint is incorrectly formed")
show warnings;
Level Code Message
Warning 150 Create table `mysqld.1`.`t2` with foreign key constraint failed. Referenced table `mysqld.1`.`t1` not found in the data dictionary close to foreign key(a) references t1(a)) engine=innodb. Error1005 Can't create table `test`.`t2` (errno: 150 "Foreign key constraint is incorrectly formed")
Warning 1215 Cannot add foreign key constraint
alter table t1 add foreign key(b) references t1(a); ERROR HY000: Can't create table `test`.`#sql-temporary` (errno: 150 "Foreign key constraint is incorrectly formed")
show warnings;
Level Code Message
Warning 150 Alter table `mysqld.1`.`t1` with foreign key constraint failed. Referenced table `mysqld.1`.`t1` not found in the data dictionary close to foreign key(b) references t1(a). Error1005 Can't create table `test`.`#sql-temporary` (errno: 150 "Foreign key constraint is incorrectly formed")
Warning 1215 Cannot add foreign key constraint
create temporary table t2(a int, foreign key(a) references t1(a)) engine=innodb; ERROR HY000: Can't create table `test`.`t2` (errno: 150 "Foreign key constraint is incorrectly formed")
show warnings;
Level Code Message
Warning 150 Create table `test`.`t2` with foreign key constraint failed. Temporary tables can't have foreign key constraints. Error1005 Can't create table `test`.`t2` (errno: 150 "Foreign key constraint is incorrectly formed")
Warning 1215 Cannot add foreign key constraint for `t2`
alter table t1 add foreign key(b) references t1(a); ERROR HY000: Can't create temporary table for ALTER TABLE `test`.`t1` (errno: 150 "Foreign key constraint is incorrectly formed")
show warnings;
Level Code Message
Warning 150 Alter table `test`.`t1` with foreign key constraint failed. Temporary tables can't have foreign key constraints. Error1005 Can't create temporary table for ALTER TABLE `test`.`t1` (errno: 150 "Foreign key constraint is incorrectly formed")
Warning 1215 Cannot add foreign key constraint for `t1`
drop table t1;
create table t1(a int not null primary key, b int, key(b)) engine=innodb;
alter table t1 add foreign key(a,b) references t1(a); ERROR42000: Incorrect foreign key definition for 'foreign key without name': Key reference and table reference don't match
show warnings;
Level Code Message Error1239 Incorrect foreign key definition for 'foreign key without name': Key reference andtable reference don't match
drop table t1;
create table t1(a int not null primary key, b int, key(b)) engine=innodb;
alter table t1 add foreign key(a) references t1(a,b); ERROR42000: Incorrect foreign key definition for 'foreign key without name': Key reference and table reference don't match
show warnings;
Level Code Message Error1239 Incorrect foreign key definition for 'foreign key without name': Key reference andtable reference don't match
drop table t1;
create table t1 (f1 integer not null primary key) engine=innodb;
alter table t1 add constraint c1 foreign key (f1) references t1(f1) on update set null; ERROR HY000: Can't create temporary table for ALTER TABLE `test`.`t1` (errno: 150 "Foreign key constraint is incorrectly formed")
show warnings;
Level Code Message
Warning 150 Alter table `test`.`t1` with foreign key `c1` constraint failed. You have defined a SET NULL condition but column 'f1' is defined as NOT NULL. Error1005 Can't create temporary table for ALTER TABLE `test`.`t1` (errno: 150 "Foreign key constraint is incorrectly formed")
Warning 1215 Cannot add foreign key constraint for `t1`
create table t2(a int not null, foreign key(a) references t1(f1) on delete set null) engine=innodb; ERROR HY000: Can't create table `test`.`t2` (errno: 150 "Foreign key constraint is incorrectly formed")
show warnings;
Level Code Message
Warning 150 Create table `test`.`t2` with foreign key (a) constraint failed. You have defined a SET NULL condition but column 'a' is defined as NOT NULL. Error1005 Can't create table `test`.`t2` (errno: 150 "Foreign key constraint is incorrectly formed")
Warning 1215 Cannot add foreign key constraint for `t2`
drop table t1;
create table t1 (id int not null primary key, f1 int, f2 int, key(f1)) engine=innodb;
create table t2(a char(20), key(a), foreign key(a) references t1(f1)) engine=innodb; ERROR HY000: Can't create table `test`.`t2` (errno: 150 "Foreign key constraint is incorrectly formed")
show warnings;
Level Code Message
Warning 150 Create table `test`.`t2` with foreign key (a) constraint failed. Field type or character set for column 'a' does not match referenced column 'f1'. Error1005 Can't create table `test`.`t2` (errno: 150 "Foreign key constraint is incorrectly formed")
Warning 1215 Cannot add foreign key constraint for `t2`
drop table t1;
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(vorverarbeitet am 2026-10-08)
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